The realization that everything would be okay regarding the obesity epidemic occurred to me in a doughnut shop. It was the last week of my employment as a weight loss doctor and for years, my clinic had been a junk food free zone. This was not because I set rules based on a notion that junk food is bad for a person. I didn't and I don't really have much worry about sugary snacks. It just happened as a sort of accidental byproduct of what we were doing. If you talk about diet rules all day and see how hard the patients are working to eat better, it just feels wrong to have a big box of doughnuts in the break-room...or powdered sugar on your slacks.

So, there I was in Dunkin' Donuts to pick up a dozen fatty sugar bombs as an ironic goodbye gesture for my co-workers. When I got to the counter, at the register, I saw what was on display for an impulse buy: a Dunkin' Donuts protein bar.

As Austin Powers said, "Yay! Capitalism!"

Here, in the symbolic heart of the environmental disruption of our food supply was the beginning of the end of obesity. Actually, my very first thought was, "these people will do anything for money." 
I believe that the future shows signs of being a healthier place for us, not by restricting choice or technology, but by using those two things to our biological and social advantage. What's occurring on the television, online, and in the grocery store tells us much about where we are going.

Take Nature Valley granola bars, for instance. I have been pointing out this brand to my patients for years as an example of a company projecting an image of health for marketing purposes without any knowledge or concern about what makes a person healthy. The ingredients on a granola bar are fine, they won't hurt you, but they aren't suitable for people watching their weight. It's essentially a candy bar for people who can't admit to themselves that they want something sweet. In any case, instead of broadcasting that the bar is made with whole grain, or is low fat, as in past years, the new label broadcasts: Protein.

This, in fact, represents a change in the bar's recipe. The company spotted the protein trend, likely asked their target demographic what they are looking for in a healthy snack and put it in the bars. Whole grain oats last decade, protein this decade, as long as it sells. It doesn't matter whether the company is doing it for ethical reasons, health reasons or financial reasons. It also doesn't matter if the consumer is seeking foods with protein broadcast on the label because they are dieting, weight lifting, following paleo, Atkins, protein power, or have read Gary Taubes. It doesn't matter if people are even doing it deliberately at all.

Trends occur for a multitude of reasons, but the need for profit ensures that companies listen, eventually, to their consumers. About 20 years into the espresso drink trend, even McDonald's picked up on the fact that it might be smart to try something different with its coffee. Thus we find hope for the modern world.

When I finally got to start a weight loss clinic (after asking my employers for years) in 2011, one of my most common discussions with patients was "how to find protein." At that point in time, in the mid-west anyway, convenient stores and grocery stores were not yet aware that these products were important. At our local grocery chain, a couple of brands of protein powder were kept in the functional food section of the store. Right next to Pedialyte and Ensure, you could pick up protein powder marketed as a muscle builder for weight lifters. That's what people in 2011 thought protein was for. It was a food that was semi-medicinal, available right near the pharmacy.

Now, protein has become its own food group. Just as the grocery aisles highlight important items that are available in that row, such as "pasta" or "paper products," you can now find a label for "protein" in our local CVS. In the "protein aisle" are a host of bars (what we used to call energy bars, when we wanted energy, but now call protein bars), powders and cookies. 

Quaker Oats now makes a high protein oatmeal. This is likely a response to consumers, who used to go through the trouble of adding protein powder to the oatmeal themselves.

Cereals such as Cheerios and Special K come in high protein versions too. When I see "protein" marketed this way, I chuckle to myself, wondering how it would work to have signs for "fat" and "carbohydrate" in other aisles. From my perspective, it's okay if CVS thinks protein is a food group, or if consumers don't know exactly what it is, as long as they know they want it. Changing the food environment will work, regardless of how well-informed that change is. 

Coca Cola now sells protein. In 2014, as part of its ongoing mission to save the world from obesity (or maybe they wanted to make money, always hard to guess with the folks at Coke), the company purchased Core Power, which makes widely available shakes which I used to recommend to patients. Core Power took the consumer's desire for protein and married it to the consumer's interest in "real" ingredients and marketed their shakes as more "natural" than other brands.

This worked so well, that Coca Cola noticed them, bought them and began making a high protein milk called Fairlife, which has twice the protein and one half the carbohydrate as regular milk (at twice the price). I like it, but then again, I like milk just fine and drink a ton of it for an adult (I also drink a ton of Coke for an adult, truth be told). Is Coca Cola pushing protein a good thing? From an obesity doctor perspective, it's a great thing. People will consume what's displayed in the grocery store, or placed on the counter at the doughnut shop. If they don't, those things will not be there for long (Yay, Capitalism, once more). The Coca Cola company is good at spreading what it sells, opening up new markets and influencing what goes into our bodies. The more Coca Cola gets involved in selling the protein trend, the better for our weight. The fact that protein is the buzz word for corporations and food marketers at this point in time bodes well for our obesity problem.

Protein is now on the cover of the package. It's getting top billing for once. This represents a new public consensus that we are leaving the era of fat, cholesterol and sugar concern and entering a new one. A period where people consciously seek protein. They have been unconsciously seeking it all along, but we can now align what little of our eating is controlled by the decision-making part of the brain with the unconscious needs of hypothalamus and the body. To the extent that the "food industry" has been a willing or unwilling aide to the obesity epidemic, it will now (not because of intelligence or moral rectitude, but by the mechanisms inherent in capitalism) work against the obesity trend through the math of protein leverage. The more protein available, advertised, marketed, displayed by companies with which we are already familiar, the more we will consume. 

My daughter feigning enthusiasm for a somewhat ridiculous product displayed at the local grocery. 

There is some irony in the big agribusiness and food giants increasing protein in their products and charging us for the improvement. As an occupational medicine doctor in Cedar Rapids, Iowa, I had the unusual experience of touring the plants responsible for almost every aspect of turning rows of corn and wheat from the fields into foods which can be boxed and shipped and stored for several months and still taste wonderful. In our mid-western city, we have a system of railways which would make Dr. Seuss or Rube Goldberg proud in its complexity. Corn, oats and wheat arrive on rail-cars from all over the continent and Cargill, ADM, General Mills, Quaker Oats and a variety of smaller plants, cooperate to rip these grains apart for every bit of sellable energy or chemical power they contain. The official civic slogan for Cedar Rapids is the City of Five Seasons, but its colloquial nickname is the "City of Five Smells." This is more or less apt, as grain cooking, milling, fermenting all envelop their own fragrance. One potent local aroma is caused by the processing of a corn kernel byproduct called furfural which can be used a flavorant or in making vanilla, but which, when being processed, actually smells as if your little brother drank vanilla liqueur then threw up in your football cleats and left them out in the sun to dry. The fifth smell, however, is simply "Crunch Berries" and it is worth tolerating all the others for this once a week treat (depending on wind conditions). 

I picture this whole complicated operation having now to fit reverse switches on several of the rails and pipes. After all the trouble taken to remove the hard nutritious bit to make wheat germ and save the yummy carbs for rolling into Wheaties flakes, the customer now wants the protein added back in!

It was John Harvey Kellogg in Battle Creek (The doctor's brother, W.K., became the cereal maker) who convinced the country to eat a high carbohydrate breakfast for our health (and for the health of the pigs and chickens he didn't think we should disturb). But now, Special K is one of the proudest promoters of protein-enhanced cereal, bars and shakes (Incidentally, they've done a better job putting the word "protein" on their packaging, than they have putting the stuff in the actual products...their protein shakes have the same content as milk). It seems strange for companies to do all this processing gymnastics just to bring back the breakfast macronutrient balance we had 150 years ago. Bacon, eggs and toast seems a well-designed combo to me.

The math of protein leverage estimates that as you increase protein percent in the diet, calories will decrease -about 100 calories per 5% was my observation from studying patient journals.  My patients and I seemed to have hit upon a solid solution for the obesity problem: just add protein. I took this notion to heart so deeply that my standard advice to anyone asking me about weight loss was no longer that they needed to come see me in the clinic, begin to track their intake and strive for a perfect balance of nutrients. I began telling people informally: just drink a protein shake a day for the next few months and see what happens. What would be the ramifications if this advice became the common wisdom? What if the population became convinced that protein was the solution to weight problems and universally prevented or treated the condition with 25 or 30 extra grams in the morning, as I've advocated to all of my patients? Simpson and Raubenheimer, the developers of the Protein Leverage hypothesis, have some thoughts on this:

"Perhaps, then, augmenting the proportion of protein in the daily diet offers a means of ameliorating obesity by taking advantage of the inhibition of intake once the protein target is reached. Three things take some of the gloss from this optimistic suggestion." (The Nature of Nutrition, page 185) They go on to discuss the three things: 1) it might not work, 2) it would be bad for the environment to increase livestock for our consumption, but most importantly, 3) more protein may actually be worse for human health. This last objection would be a cruel irony. We all shift our consumption to match the latest health consensus, that high protein is better than other diets, only to find out that it causes unintended health problems that are worse than the ones we are trying to avoid (does this sound familiar?).

We will avoid the discussion of optimum land usage as being outside the scope of our immediate concern. But the other two issues must be addressed if we are to contend that protein leverage solves the obesity conundrum. We must be able to find evidence that it safely works without causing harm to our bodies. We can't repeat the mistakes of the low fat crowd, forcing a new diet on an unwary populace, based on early data that haven't been rigorously tested, just because we appreciate the logic of the newer answer.

There are only three macronutrients in the diet. Have scientists, in addition to looking at the consequences of high carb diets and high fat diets, looked at the health consequences of high protein diets?

Luckily for our current discussion, they have. Regarding the efficacy of higher protein diets for weight loss, many trials and reviews have corroborated the principle of protein leverage by testing higher versus lower protein diets while controlling the carbohydrate and fat eaten. For example, in 2005, David Weigle and colleagues published a trial comparing diets of equal calories that contained either normal, or twice normal protein (15% and 30% respectively). The authors point out, in their introduction, that low carb diets (which are high fat) and low fat diets seem to work equally well and that our current thinking requires dietary fat to make fat in our bodies. "This paradox could be explained if it is the high protein content, rather than the lower carbohydrate content of low carbohydrate diets that offsets the deleterious effect of high fat intakes and results in weight loss." 

The researchers assessed baseline calorie needs, metabolism and a variety of hormone levels during two weeks in which the subjects were fed diets of 15% protein, 50% carbohydrate, and 35% fat (the usual diet considered U.S. standard). After two weeks of this, the researchers doubled the protein to 30% but required the subjects to eat all of the food provided, which kept calories the same. Eating higher protein at the same calorie level did not produce weight loss, although the subjects rated hunger much lower and fullness much higher during the double protein period. Dr. Weigle and his colleagues then kept the protein percent at 30 for the following 12 weeks and allowed subjects to eat as much as they felt they needed to satisfy hunger. Without being forced to maintain their previous 2400 calories (on average) per day, the study subjects immediately began to consume less. They continued eating less until the study ended. This resulted in an average weight loss of 5 kg (11.3 pounds). The authors noted that when the subjects ate less on a high protein diet, they did so by allowing fat percent, rather than carbohydrate, to decrease. Thus, they lost weight while maintaining carbohydrate intake, which suggests that low fat diets may simply work by increasing protein. An important finding is that the higher protein diet did not produce weight loss when calories were maintained. The weight loss came only after the subjects were allowed to let the protein's appetite suppressing effects to work. The laws of physics were not defied by the study and calories still accounted for weight loss. While protein may change our metabolic rate, or cause more energy to be used for digestion, in this study, those effects were not found and the appetite suppressing effect and eating less were the not-so-mysterious cause of the weight loss.

Why would the body suppress appetite in the presence of increased protein? Doesn't the protein leverage framework propose that humans regulate diet to get maximum protein? Not exactly. The theory is that the body seeks an optimum amount of protein for health, reproduction and longevity.

This brings us to the more critical concern of whether eating this way could actually harm human health. The weight losing aspect and appetite suppressing effects of high protein diets suggest that they work because the body is trying to protect itself from something harmful. Satiety from the food could be seen as confirming you've eaten the right thing, but early satiety, so much so that one naturally eats too few calories and loses weight, might suggest that the diet used for weight loss is actually unhealthy.

Simpson and Raubenheimer suggest that we can consider this question by examining other species. An entire chapter in The Nature of Nutrition is dedicated possible mechanisms whereby species balance the risks and benefits of protein intake as they relate to growth, reproduction and longevity. In a discussion of the concept of caloric restriction and longevity, they point out that restriction of protein is, in fact, the mediator of the life extending properties of CR diets. They report (with Lee and colleagues, PNAS, 2008, this is free) that fruit flies can live equal amounts of time on a wide variety of calories, but time of death is directly related to the ratio of protein to carbohydrate in the flies' diet. As they diluted the carbohydrate with more and more protein, the lifespan grew progressively shorter. There was a clear "dose-response" relationship between protein amount and risk of mortality, with risk growing in step-wise fashion with each increase in protein given. This is shown to be true in crickets and rodents as well. Specific dietary manipulations suggest that it may be particular combinations of amino acids that act as the shorteners of life, with rat studies showing restricting methionine to be necessary for life extension. While the pathways for a potential toxicity of protein are not known, there are corollary studies in humans that find higher amounts of protein showing negative health effects.

N. Santesso and colleagues published a review of dietary protein effects on health outcomes in the European Journal of Clinical Nutrition, in 2012. They looked at over 100 studies of higher versus lower protein diets published in major journals to conclude that "higher protein diets probably improve adiposity, blood pressure and triglyceride levels, but these effects are small and need to be weighed against potential for harms." The harms examined in the study included more gastrointestinal symptoms and muscle cramping in high protein groups, as well as some studies reporting increases in creatinine (which goes up with kidney stress). The analysis was based on 3 month outcomes, so did not have anything to say about longevity. 

In 2014, a paper by Morgan Levine and colleagues, caused a stir by suggesting that lower protein, not higher protein, was protective against several chronic diseases and risk of death. The results were published in the journal Cell Metabolism. Looking at the NHANES database and assigning individuals to either a "low protein" category of <10%, or "high protein" category of  >20%, the authors showed that lower protein reduced risk of mortality from all causes, including cancer and diabetes. This was true only for the age group from 50-65 years old. Those older than 65 had improvement in longevity with higher protein diets. Several experts expressed criticism of this study in interviews and social media, particularly objecting to the idea of categorizing diet by using only one dietary recall questionnaire and assuming that individuals do not change diet over decades of follow up. Nevertheless, the suggestion that there may be negative consequences of a higher protein diet need to be taken seriously.

The companies which fill our grocery store with the products we buy haven't heard of protein leverage. They aren't trying to design an optimal ecosystem from which we forage for optimum nutrition. They are selling stuff. The Crunch Berry people are neither trying to hurt us or help us. They just want to give us what we want. Right now, we are beginning a high protein experiment. This took several years to ramp up and would take many more to ramp back down. We are very likely to see manifestations of this change at the group level.

The protein leverage framework starts with the idea that the body has inherent wisdom which works to control food intake. It's possible that there will be no negative consequences of the protein revolution, as our bodies naturally restore us to an optimum diet, in a better ecosystem, where protein is more readily available. Perhaps "protein water" is simply part of a needed re-balancing.

But I think that's overly optimistic. Bodies seem to respond on a bell curve, so what works for a little needed weight loss for one person, or most, is bound to induce too much weight loss in a few. Just as the "fat is bad" notion is, to this day, mistakenly informing school lunch policies for children, the "protein is good" notion has the potential to cause harm, or at least stupid choices in the near future.