White Meat May Be as Cholesterol-Raising as Red

White Meat May Be as Cholesterol-Raising as Red.jpeg

In light of recommendations for heart healthy eating from national professional organizations encouraging Americans to limit their intake of meat, the beef industry commissioned and co-wrote a review of randomized controlled trials comparing the effects of beef versus chicken and fish on cholesterol levels published over the last 60 years. They found that the impact of beef consumption on the cholesterol profile of humans is similar to that of fish and/or poultry--meaning that switching from red meat to white meat likely wouldn't make any difference. And that's really no surprise, given how fat we've genetically manipulated chickens to be these days, up to ten times more fat than they had a century ago (see Does Eating Obesity Cause Obesity?).

There are a number of cuts of beef that have less cholesterol-raising saturated fat than chicken (see BOLD Indeed: Beef Lowers Cholesterol?), so it's not so surprising that white meat was found to be no better than red, but the beef industry researchers conclusion was that "therefore you can eat beef as part of a balanced diet to manage your cholesterol."

Think of the Coke versus Pepsi analogy. Coke has less sugar than Pepsi: 15 spoonfuls of sugar per bottle instead of 16. If studies on blood sugar found no difference between drinking Coke versus Pepsi, you wouldn't conclude that "Pepsi may be considered when recommending diets for the management of blood sugars," you'd say they're both equally as bad so we should ideally consume neither.

That's a standard drug industry trick. You don't compare your fancy new drug to the best out there, but to some miserable drug to make yours look better. Note they didn't compare beef to plant proteins, like in this study published in the American Journal of Clinical Nutrition. As I started reading it, though, I was surprised that they found no benefit of switching to a plant protein diet either. What were they eating? You can see the comparison in Switching from Beef to Chicken & Fish May Not Lower Cholesterol.

For breakfast, the plant group got a kidney bean and tomato casserole and a salad, instead of a burger. And for dinner, instead of another burger, the plant protein group just got some boring vegetables. So why was the cholesterol of the plant group as bad as the animal group? They had the plant protein group eating three tablespoons of beef tallow every day--three tablespoons of straight beef fat!

This was part of a series of studies that tried to figure out what was so cholesterol-raising about meat--was it the animal protein or was it the animal fat? So, researchers created fake meat products made to have the same amount of saturated fat and cholesterol by adding extracted animal fats and cholesterol. Who could they get to make such strange concoctions? The Ralston Purina dog food company.

But what's crazy is that even when keeping the saturated animal fat and cholesterol the same (by adding meat fats to the veggie burgers and making the plant group swallow cholesterol pills to equal it out), sometimes they still saw a cholesterol lowering advantage in the plant protein group.

If you switch people from meat to tofu, their cholesterol goes down, but what if you switch them from meat to tofu plus lard? Then their cholesterol may stay the same, though tofu and lard may indeed actually be better than meat, since it may result in less oxidized cholesterol. More on the role of oxidized cholesterol can be found in my videos Does Cholesterol Size Matter? and Arterial Acne.

Just swapping plant protein for animal protein may have advantages, but if you really want to maximize the power of diet to lower cholesterol, you may have to move entirely toward plants. The standard dietary advice to cut down on fatty meat, dairy, and eggs may lower cholesterol 5-10%, but flexitarian or vegetarian diets may drop our levels 10 to 15%, vegan diets 15 to 25%, and healthier vegan diets can cut up to 35%, as seen in this study out of Canada showing a whopping 61 point drop in LDL cholesterol within a matter of weeks.


You thought chicken was a low-fat food? It used to be a century ago, but not anymore. It may even be one of the reasons we're getting fatter as well: Chicken Big: Poultry and Obesity and Infectobesity: Adenovirus 36 and Childhood Obesity.

Isn't protein just protein? How does our body know if it's coming from a plant or an animal? How could it have different effects on cardiovascular risk? See Protein and Heart Disease, another reason why Plant Protein [is] Preferable.

Lowering cholesterol in your blood is as simple as reducing one's intake of three things: Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero.

What about those news stories on the "vindication" of saturated fat? See the sneaky science in The Saturated Fat Studies: Buttering Up the Public and The Saturated Fat Studies: Set Up to Fail.

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: CDC/Debora Cartagena via Freestockphotos.biz. This image has been modified.

Original Link

White Meat May Be as Cholesterol-Raising as Red

White Meat May Be as Cholesterol-Raising as Red.jpeg

In light of recommendations for heart healthy eating from national professional organizations encouraging Americans to limit their intake of meat, the beef industry commissioned and co-wrote a review of randomized controlled trials comparing the effects of beef versus chicken and fish on cholesterol levels published over the last 60 years. They found that the impact of beef consumption on the cholesterol profile of humans is similar to that of fish and/or poultry--meaning that switching from red meat to white meat likely wouldn't make any difference. And that's really no surprise, given how fat we've genetically manipulated chickens to be these days, up to ten times more fat than they had a century ago (see Does Eating Obesity Cause Obesity?).

There are a number of cuts of beef that have less cholesterol-raising saturated fat than chicken (see BOLD Indeed: Beef Lowers Cholesterol?), so it's not so surprising that white meat was found to be no better than red, but the beef industry researchers conclusion was that "therefore you can eat beef as part of a balanced diet to manage your cholesterol."

Think of the Coke versus Pepsi analogy. Coke has less sugar than Pepsi: 15 spoonfuls of sugar per bottle instead of 16. If studies on blood sugar found no difference between drinking Coke versus Pepsi, you wouldn't conclude that "Pepsi may be considered when recommending diets for the management of blood sugars," you'd say they're both equally as bad so we should ideally consume neither.

That's a standard drug industry trick. You don't compare your fancy new drug to the best out there, but to some miserable drug to make yours look better. Note they didn't compare beef to plant proteins, like in this study published in the American Journal of Clinical Nutrition. As I started reading it, though, I was surprised that they found no benefit of switching to a plant protein diet either. What were they eating? You can see the comparison in Switching from Beef to Chicken & Fish May Not Lower Cholesterol.

For breakfast, the plant group got a kidney bean and tomato casserole and a salad, instead of a burger. And for dinner, instead of another burger, the plant protein group just got some boring vegetables. So why was the cholesterol of the plant group as bad as the animal group? They had the plant protein group eating three tablespoons of beef tallow every day--three tablespoons of straight beef fat!

This was part of a series of studies that tried to figure out what was so cholesterol-raising about meat--was it the animal protein or was it the animal fat? So, researchers created fake meat products made to have the same amount of saturated fat and cholesterol by adding extracted animal fats and cholesterol. Who could they get to make such strange concoctions? The Ralston Purina dog food company.

But what's crazy is that even when keeping the saturated animal fat and cholesterol the same (by adding meat fats to the veggie burgers and making the plant group swallow cholesterol pills to equal it out), sometimes they still saw a cholesterol lowering advantage in the plant protein group.

If you switch people from meat to tofu, their cholesterol goes down, but what if you switch them from meat to tofu plus lard? Then their cholesterol may stay the same, though tofu and lard may indeed actually be better than meat, since it may result in less oxidized cholesterol. More on the role of oxidized cholesterol can be found in my videos Does Cholesterol Size Matter? and Arterial Acne.

Just swapping plant protein for animal protein may have advantages, but if you really want to maximize the power of diet to lower cholesterol, you may have to move entirely toward plants. The standard dietary advice to cut down on fatty meat, dairy, and eggs may lower cholesterol 5-10%, but flexitarian or vegetarian diets may drop our levels 10 to 15%, vegan diets 15 to 25%, and healthier vegan diets can cut up to 35%, as seen in this study out of Canada showing a whopping 61 point drop in LDL cholesterol within a matter of weeks.


You thought chicken was a low-fat food? It used to be a century ago, but not anymore. It may even be one of the reasons we're getting fatter as well: Chicken Big: Poultry and Obesity and Infectobesity: Adenovirus 36 and Childhood Obesity.

Isn't protein just protein? How does our body know if it's coming from a plant or an animal? How could it have different effects on cardiovascular risk? See Protein and Heart Disease, another reason why Plant Protein [is] Preferable.

Lowering cholesterol in your blood is as simple as reducing one's intake of three things: Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero.

What about those news stories on the "vindication" of saturated fat? See the sneaky science in The Saturated Fat Studies: Buttering Up the Public and The Saturated Fat Studies: Set Up to Fail.

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: CDC/Debora Cartagena via Freestockphotos.biz. This image has been modified.

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Flax Seeds Can Have Profound Effect on Hypertension

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A recent article in the journal, Meat Science, acknowledged that a sector of the population perceives meat as a food that is detrimental to their health because of studies associating meat consumption with heart disease and cancer. So, the article continues, meat consumers may look for healthier food alternatives as a means to maintain good health, which represents a good opportunity for the meat industry to develop some new products. The industry felt that natural foods could be added to meat to reach those health-oriented consumers by boosting antioxidants levels, for example. Foods like flax seeds and tomatoes are healthy, associated with reduced risks of cancer and cardiovascular disease. So by making flax-y tomato burgers, they figure they can reduce saturated fat intake and maybe eat less sugar somehow. Wouldn't it be easier to just cut out the middle-cow and eat flax seeds ourselves?

Flax seeds have been described as a "miraculous defense against some critical maladies." I'm a fan of flax, but this title seemed a bit over-exuberant; I figured something just got lost in translation, but then I found a prospective, double-blinded, placebo-controlled, randomized trial--you know how hard that is in a nutrition study? For drugs, it's easy: you have two identical looking pills, one's active, one's placebo, and until the end of the study, neither the researcher nor the patient has any idea which is which, hence "double blind." But people tend to notice what they're eating. So how did they sneak a quarter cup of ground flax seeds into half of the people's diets without them knowing? They created all these various flax or placebo containing foods, and even added bran and molasses to match the color and texture, so it was all a big secret until six months later when they broke the code to see who ate which.

Why test it on hypertension? Because having a systolic blood pressure over 115--that's the top number--may be the single most important determinant for death in the world today. If you take a bunch of older folks, most of them on an array of blood pressure pills, and don't improve their diet at all, despite the drugs, they may start out on average hypertensive and stay hypertensive six months later. But those who were unknowingly eating ground flaxseeds every day, dropped their systolic blood pressure about ten points, and their diastolic, the lower number, by about seven points. That might not sound like a lot, but a drop like that could cut stroke risk 46 percent and heart disease 29 percent, and that ten point drop in the top number could have a similar effect on strokes and heart attacks. And for those that started out over 140, they got a 15-point drop.

In summary, flaxseed induced one of the most potent antihypertensive effects ever achieved by a dietary intervention. In other words, the magnitude of this decrease in blood pressure demonstrated by dietary flaxseed, is as good or better than other nutritional interventions and comparable to many drugs, which can have serious side effects. And they're not exaggerating about the comparable to drugs bit. The flax dropped systolic and diastolic up to 15 and 7. Compare that to powerful ACE inhibitors like Vasotec, which may only drop pressures five and two, and calcium channel blockers like Norvasc or Cardizem which drop pressures eight and three. Side effects of these drugs include a large list of serious medical issues, as seen in my video Flax Seeds for Hypertension, compared to the side effect of flax seeds, "its pleasant nutty flavor."

During the six-month trial there were strokes and heart attacks in both groups, though. Even if the flax seeds can cut risk in half, any avoidable risk is unacceptable. Isn't high blood pressure just inevitable as we get older? No - the prevalence of hypertension does increase dramatically with age, but not for everyone. People who eat more plant-based diets or keep their salt intake low enough tend not to exhibit any change in blood pressure with advancing age. It's always better to prevent the disease in the first place.

And that's not all flax can do. Check out:

Hibiscus tea may help with high blood pressure as well: Hibiscus Tea vs. Plant-Based Diets for Hypertension

Diet can also play an important role in preventing heart disease (How Not to Die from Heart Disease and One in a Thousand: Ending the Heart Disease Epidemic) and diabetes (How Not to Die from Diabetes and Plant-Based Diets and Diabetes). In some cases diet can even reverse some of the worst ravages of high blood pressure: How Not to Die from High Blood Pressure and Kempner Rice Diet: Whipping Us Into Shape.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Veganbaking.net / Flickr

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Paleo Diet May Undermine Benefit of CrossFit Exercise

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Much of the low-carb and paleo reasoning revolves around insulin. To quote a paleo blogger, "carbohydrates increase insulin, the root of all evil when it comes to dieting and health." So the logic follows that because carbs increase insulin, we should stick mostly to meat, which is fat and protein with no carbs, so no increase in insulin, right?

Wrong.

We've known for half a century that if you give someone just a steak: no carbs, no sugar, no starch; their insulin goes up. Carbs make our insulin go up, but so does protein.

In 1997 an insulin index of foods was published, ranking 38 foods to determine which stimulates higher insulin levels. Researchers compared a large apple and all its sugar, a cup of oatmeal packed with carbs, a cup and a half of white flour pasta, a big bun-less burger with no carbs at all, to half of a salmon fillet. As you can see in the graph in my video Paleo Diets May Negate Benefits of Exercise, the meat produced the highest insulin levels.

Researchers only looked at beef and fish, but subsequent data showed that that there's no significant difference between the insulin spike from beef, chicken, or pork--they're all just as high. Thus, protein and fat rich foods may induce substantial insulin secretion. In fact, meat protein causes as much insulin release as pure sugar.

So, based on the insulin logic, if low-carbers and paleo folks really believed insulin to be the root of all evil, then they would be eating big bowls of spaghetti day in and day out before they would ever consume meat.

They are correct in believing that having hyperinsulinemia, high levels of insulin in the blood like type 2 diabetics have, is not a good thing, and may increase cancer risk. But if low-carb and paleo dieters stuck to their own insulin theory, then they would be out telling everyone to start eating plant-based. Vegetarians have significantly lower insulin levels even at the same weight as omnivores. This is true for ovo-lacto-vegetarians, lacto-vegetarians, and vegans. Meat-eaters have up to 50% higher insulin levels.

Researchers from the University of Memphis put a variety of people on a vegan diet (men, women, younger folks, older folks, skinny and fat) and their insulin levels dropped significantly within just three weeks. And then, just by adding egg whites back to their diet, their insulin production rose 60% within four days.

In a study out of MIT, researchers doubled participants' carbohydrate intake, and their insulin levels went down. Why? Because the researchers weren't feeding people jellybeans and sugar cookies, they were feeding people whole, plant foods, lots of whole grains, beans, fruits, and vegetables.

What if we put someone on a very-low carb diet, like an Atkins diet? Low carb advocates such as Dr. Westman assumed that it would lower insulin levels. Dr. Westman is the author of the new Atkins books, after Dr. Atkins died obese with, according to the medical examiner, a history of heart attack, congestive heart failure, and hypertension. But, Dr. Westman was wrong in his assumption. There are no significant drop in insulin levels on very low-carb diets. Instead, there is a significant rise in LDL cholesterol levels, the number one risk factor for our number one killer, heart disease.

Atkins is an easy target though. No matter how many "new" Atkins diets that come out, it's still old news. What about the paleo diet? The paleo movement gets a lot of things right. They tell people to ditch dairy and doughnuts, eat lots of fruits, nuts, and vegetables, and cut out a lot of processed junk food. But a new study published in the International Journal of Exercise Science is pretty concerning. Researchers took young healthy people, put them on a Paleolithic diet along with a CrossFit-based, high-intensity circuit training exercise program.

If you lose enough weight exercising, you can temporarily drop our cholesterol levels no matter what you eat. You can see that with stomach stapling surgery, tuberculosis, chemotherapy, a cocaine habit, etc. Just losing weight by any means can lower cholesterol, which makes the results of the Paleo/Crossfit study all the more troubling. After ten weeks of hardcore workouts and weight loss, the participants' LDL cholesterol still went up. And it was even worse for those who started out the healthiest. Those starting out with excellent LDL's (under 70), had a 20% elevation in LDL cholesterol, and their HDL dropped. Exercise is supposed to boost our good cholesterol, not lower it.

The paleo diet's deleterious impact on blood fats was not only significant, but substantial enough to counteract the improvements commonly seen with improved fitness and body composition. Exercise is supposed to make things better.

On the other hand, if we put people instead on a plant-based diet and a modest exercise program, mostly just walking-based; within three weeks their bad cholesterol can drop 20% and their insulin levels 30%, despite a 75-80% carbohydrate diet, whereas the paleo diets appeared to "negate the positive effects of exercise."

I touched on paleo diets before in Paleolithic Lessons, and I featured a guest blog on the subject: Will The Real Paleo Diet Please Stand Up?

but my favorite paleo videos are probably The Problem With the Paleo Diet Argument and Lose Two Pounds in One Sitting: Taking the Mioscenic Route.

I wrote a book on low carb diets in general (now available free full-text online) and touched on it in Atkins Diet: Trouble Keeping It Up and Low Carb Diets and Coronary Blood Flow.

And if you're thinking, but what about the size of the cholesterol, small and dense versus large and fluffy? Please see my video Does Cholesterol Size Matter?

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: Vincent Lit / Flickr

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How Big Food Twists the Science

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Just like mosquitos are the vectors of spread for malaria, a landmark article published last year in one of the most prestigious medical journals, Lancet, described large food corporations as the vectors of spread for chronic disease. Unlike "infectious disease epidemics, however, these corporate disease vectors implement sophisticated campaigns to undermine public health interventions." Most mosquitoes don't have as good PR firms.

A key message was that "alcohol and ultra-processed food and drink industries use similar strategies as the tobacco industry to undermine effective public health policies and programs." What they mean by ultra-processed is things like burgers, frozen meals, chicken nuggets, fish sticks, potato chips, doughnuts and soda pop.

But how is the food industry like the tobacco industry? The "first strategy is to bias research findings." For example, Philip Morris implemented the Whitecoat project to hire doctors to publish ghost-written studies purporting to negate links between secondhand smoke and harm, publishing biased cherry-picked scientific reports to deny harm and suppress health information. In my video Food Industry-Funded Research Bias, you can see the actual industry memo describing the Whitecoat Project, designed to reverse the scientific "misconception" that secondhand smoke is harmful.

Similarly, funding from these large food corporations biases research. Studies show systematic bias from industry funding, so we get the same kind of tactics--supplying misinformation, use of supposedly conflicting evidence and hiding negative data.

The same scientists-for-hire that downplayed the risks of secondhand smoke are the same hired by the likes of the National Confectioner's Association to say candy cigarettes are A-OK as well. Of course, they declared "no conflict of interest."

The similarities between strategies used by the tobacco, alcohol, and food and drink corporations are unsurprising in view of the flow of people, funds and activities across these industries, which also have histories of joint ownership--like Philip Morris owned both Kraft and Miller Brewing.

So what's their strategy? As a former FDA commissioner described:

"The tobacco industry's strategy was embodied in a script written by the lawyers. Every tobacco company executive in the public eye was told to learn the script backwards and forwards, no deviation was allowed. The basic premise was simple-- smoking had not been proven to cause cancer. Not proven, not proven, not proven--this would be stated insistently and repeatedly. Inject a thin wedge of doubt, create controversy, never deviate from the prepared line. It was a simple plan and it worked."

Internal industry memos make this explicit, stating "doubt is our product, since it is the best means of competing with the body of fact that exists in the mind of the general public." The internal industry memos list objective number one as "to set aside in the minds of millions the false conviction that cigarette smoking causes lung cancer and other diseases; a conviction based on fanatical assumptions, fallacious rumors, unsupported claims and the unscientific statements and conjectures of publicity-seeking opportunists... [We need] to lift the cigarette from the cancer identification as quickly as possible, and to establish--once and for all--that no scientific evidence has ever been produced, presented or submitted to prove conclusively that cigarette smoking causes cancer," similar to what's now coming out from the food industry, from the same folks that brought us smoke and candy.

This is part of a series of "political" blogs which includes my video, Collaboration with the New Vectors of Disease. Why don't I just "stick to the science"? When there are billions of dollars at stake, the body of evidence can be skewed and manipulated. Funders can determine which studies are performed, how they're performed and whether or not they get published at all. That's why I think it's important to take a broader view to account for the ways the scientific method can be perverted for profit.

Here are some examples:

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

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Rinse Your Mouth After Sour Foods and Drinks

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Hibiscus tea has been found to be as effective at lowering blood pressure as a leading hypertension drug without the potential side-effects (which include everything from lack of strength to impotence, including rare cases of potentially fatal liver damage). Hibiscus, though, may have adverse effects of its own.

As I've reviewed previously in Plant-Based Diets: Oral Health, people who eat plant-based diets appear to have superior periodontal health, including less gum disease and fewer signs of inflammation, like bleeding. However, they also have twice the prevalence of dental erosions, areas on the teeth where the enamel has thinned due to more frequent consumption of acidic fruits and vegetables. Therefore, after we eat something like citrus, we should swish our mouths with water to clear the acid from our teeth.

This includes beverages. I'm a big fan of hibiscus tea, but it's not called "sour tea" for nothing. In a study highlighted in my video, Protecting Teeth from Hibiscus Tea, researchers at the University of Iowa dental school tested 25 different popular teas and found two with a pH under 3 (as acidic as orange juice or coca cola): Tazo's passion and Bigelow's red raspberry, both of which contain hibiscus as their first ingredient.

To see if these teas could actually dissolve teeth, the researchers took 30 extracted molars from people and soaked them in different teas. And indeed, out of the five teas tested, the greatest erosion came from the tea with the most hibiscus. The researchers left the tooth sitting in the tea for 25 hours straight, but this was to simulate a lifetime of exposure. The bottom line is that herbal teas are potentially erosive, particularly fruity and citrusy teas like hibiscus. To minimize the erosive potential, we can use a straw to drink the beverage. And as I mentioned above, after consuming an acidic food or drink we should also rinse our mouth with water to help neutralize the acid.

For more on the effects of hibiscus on blood pressure, see the previous video, Hibiscus Tea vs. Plant-Based Diets for Hypertension.

Are there other potential downsides to tea drinking? That's the topic of my videos: Is There Too Much Aluminum in Tea? and How Much Hibiscus Tea is Too Much?

For more on avoiding drug side-effects by choosing more natural treatments can be found in videos like:

For more on diet and oral health, see:

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: T.Kiya / Flickr

Original Link

How Fatty Foods May Affect Our Love Life

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The food industry, like the tobacco companies and other drug lords, has been able to come up with products that tap into the same dopamine reward system that keeps people smoking cigarettes, using marijuana, and eating candy bars (See Are Sugary Foods Addictive?). New research, highlighted in my video Are Fatty Foods Addictive? suggests that fat may have similar effects on the brain. If people are fed yogurt packed with butter fat, within 30 minutes they exhibit the same brain activity as those who just drank sugar water.

People who regularly eat ice cream (sugar and fat) have a deadened dopamine response in their brains in response to drinking a milkshake. It's similar to when drug abusers have to use more and more to get the same high. Frequent ice cream consumption "is related to a reduction in reward-region (pleasure center) responsivity in humans, paralleling the tolerance observed in drug addiction." Once we've so dulled our dopamine response, we may subsequently overeat in an effort to achieve the degree of satisfaction experienced previously, contributing to unhealthy weight gain.

What do fatty and sugary foods have in common? They are energy-dense. It may be less about the number of calories than their concentration. Consumption of a calorie-dilute diet doesn't lead to deadened dopamine responsivity, but a calorie-dense diet with the same number of calories does. It's like the difference between cocaine and crack: same stuff chemically, but by smoking crack cocaine we can deliver a higher dose quicker to our brain.

As an aside, I found it interesting that the control drink in these milkshake studies wasn't just water. They can't use water because our brain actually tastes water on the tongue (who knew!). So instead the researchers had people drink a solution "designed to mimic the natural taste of saliva." Ew!

Anyway, with this new understanding of the neural correlates of food addiction, there have been calls to include obesity as an official mental disorder. After all, both obesity and addiction share the inability to restrain behavior in spite of an awareness of detrimental health consequences, one of the defining criteria of substance abuse. We keep putting crap in our bodies despite the knowledge that we have a problem that is likely caused by the crap, yet we can't stop (a phenomena called the "pleasure trap").

Redefining obesity as an addiction, a psychiatric disease, would be a boon to the drug companies that are already working on a whole bunch of drugs to muck with our brain chemistry. For example, subjects given an opiate blocker (like what's done for people with heroin overdoses to block the effects of the drug) eat significantly less cheese -- it just doesn't do as much for them anymore when their opiate receptors are blocked.

Rather than taking drugs, though, we can prevent the deadening of our pleasure center in the first place by sticking to foods that are naturally calorically dilute, like whole plant foods. This can help bring back our dopamine sensitivity such that we can again derive the same pleasure from the simplest of foods (see Changing Our Taste Buds). And this is not just for people who are obese. When we regularly eat calorie dense animal and junk foods like ice cream, we can blunt our pleasure so that we may overeat to compensate. When our brain down-regulates dopamine receptors to deal with all these jolts of fat and sugar, we may experience less enjoyment from other activities as well.

That's why cocaine addicts may have an impaired neurological capacity to enjoy sex, and why smokers have an impaired ability to respond to positive stimuli. Since these all involve the same dopamine pathways, what we put into our body--what we eat--can affect how we experience all of life's pleasures.

So to live life to the fullest, what should we do? The food industry, according to some addiction specialists, "should be given incentives to develop low calorie foods that are more attractive, palatable and affordable so that people can adhere to diet programs for a long time." No need! Mother Nature beat them to it--that's what the produce aisle is for.

By starting to eat healthfully, we can actually change how things taste. Healthiest means whole plant foods, which tend to be naturally dilute given their water and fiber content. Not only is fiber also calorie-free, but one might think of it as having "negative" calories, given the fermentation of fiber in our bowel into anti-obesity compounds (as well as anti-inflammatory, anti-cancer compounds). For this reason, those eating plant-based diets eat hundreds of fewer calories without even trying. (See my video Nutrient-Dense Approach to Weight Management).

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Images thanks to Burger Austin / Flickr

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Does Animal Protein Cause Osteoporosis?

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For most of the last century, a prevailing theory within the field of nutrition was that by eating acid-forming foods such as meat, we were, in essence, at risk of peeing our bones down the toilet. And no wonder! Experiments dating back to 1920 showed over and over that if we add meat to our diet we get a big spike in the amount of calcium being lost in the urine.

And this made total sense. We had known since 1912 that meat was acid-forming within the body, and how do we buffer acid? What are in antacid (anti-acid) pills like Tums? Calcium compounds.

Meat and eggs have a lot of sulphur-containing amino acids (two to five times more than grains and beans) that are metabolized into sulphuric acid, which the body buffers with calcium compounds. And where is calcium stored in the body? The skeleton. So the thinking was that every time we ate a steak, our body would pull calcium from our bones, bit by bit, and over time this could lead to osteoporosis. Based on 26 such studies, for every 40 grams of protein we add to our daily diet, we pee out an extra 50 mg of calcium. We only have about two pounds of calcium in our skeleton, so the loss of 50 grams a day would mean losing close to 2% of our bone calcium every year. By the end of the 20th century, there was little doubt that acid-forming diets would dissolve our bones away.

But if we actually look at the studies done on protein intake and bone health, that's not what we find. So, where's the flaw in the logic? Meat leads to acid, which leads to calcium loss, which leads to bone loss, right?

Well, it's uncontroversial that protein results in greater calcium excretion, but we've just been assuming it's coming from the bone--where else could the extra calcium dumped in our urine be coming from but our bones?

One study appeared to solve the mystery. An intrepid group of researchers tried feeding a group of volunteers radioactive calcium and then put them on a high protein diet. What happens when we put people on a high protein diet? The amount of calcium in their urine shoots up, and indeed that's just what happened. But here's the big question, was that extra calcium in their urine radioactive or not? To everyone's surprise, it was radioactive. This meant that the excess calcium in their urine was coming from their diet, not from their bones.

What seemed to be happening is that the excess protein consumption boosted calcium absorption, from down around 19% up to 26%. All of a sudden there was all this extra calcium in the blood, so presumably the kidneys are like "whoa, what are we going to do with it all?" So they dump it into the urine. 90% of the extra calcium in the urine after eating a steak doesn't appear to be coming from our bones but from our diet. We're not sure why protein boosts calcium absorption. Maybe protein increases the solubility of calcium by stimulating stomach acid production? Whatever the reason, there was indeed more calcium lost, but also more calcium gained such that in the end, most of that extra calcium is accounted for. In effect, more calcium is lost in the urine stream, but it may be compensated by less loss of calcium through the fecal stream.

This was repeated with even more extreme diets--an acid-forming five-burgers-a-day-worth-of-animal protein diet that limited fruits and vegetables versus an alkaline diet emphasizing fruits and vegetables. More calcium in the urine on burgers, but significantly greater calcium absorption, such that at the end it was pretty much a wash.

Other studies have also since supported this interpretation. Here's an ingenious one: Feed people a high animal protein diet but add in an alkali salt to neutralize the acid. The old thinking would predict that there would be no calcium loss since there is no excess acid to buffer, but no, even though the acid load was neutralized, there was still the excess urinary calcium, consistent with the radioactive isotope study, challenging the "long-standing dogma that animal protein consumption results in a mild acidosis promoting the increased excretion of calcium."

So if our body isn't buffering the acid formed from our diet with our bones, how is it neutralizing the acid? Maybe with our muscles. Alkaline diets may protect our muscle mass! I cover that in my video Testing Your Diet with Pee and Purple Cabbage.

Now the boost in calcium absorption can only compensate if we're taking enough in. For example, dietary acid load may be associated with lower bone mineral density in those getting under 800mg a day. Plant Protein is Preferable to animal protein for a variety of reasons (tends to have less methionine, is less IGF-1 promoting, etc.), but it's not clear how much of an advantage it has when it comes to bone health.

I previously touched on this topic in my video Is Protein Bad to the Bone? But I promised I'd take a deeper dive, hence my video Alkaline Diets, Meat & Calcium Loss.

-Michael Greger, M.D.

Note to chemistry geeks: Yes, I know it's the calcium salt anions that actually do the buffering (carbonate in Tums and phosphate in bones), but I'm trying my best to simplify for a largely lay audience. I'll make it up to you with some kitchen chemistry (actually bathroom chemistry!) in my Testing Your Diet video.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image Credit: PD Art / Wikimedia Commons

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