Recently I came across a new book called The Microbiome Diet. It is based on the idea that the colonies of bacteria in our guts are “the secret to healthy weight loss and to feeling healthy, energized, optimistic, and at the top of [our] game.” Author Raphael Kellman prescribes a three-phase plan that entails including prebiotic and probiotic “superfoods” such as yogurt, sauerkraut, garlic, and tomatoes in every meal.
Like most inventors of new diets, Kellman argues that his diet is needed because existing diets are based on bad information and consequently don’t work. He writes, “I believe that this book will challenge everything you know about the causes of obesity—and about the kind of diet that can successfully overcome it.”
It’s easy to laugh at Kellman’s suggestion that his diet is the only true solution to the problem of diet-related health problems. Only a few hundred people in the entire world are currently following it and it’s unlikely that more than a few thousand ever will. The notion that the only diet that’s truly good enough for humans would come along for the first time in 2014 and then pass into oblivion having made barely a ripple seems far fetched. But what about some of the other new diets, the ones that have caught on in a big way, such as the Paleo diet and the gluten-free diet and the high-fat version of the low-carb diet? The creators of each of these diets has also argued that his is needed because no previously existing diet was good enough to yield optimal health. Is any of these diets really needed? No.
What allows the creators of such diets to convince many people that a new way of eating is needed is the fact that the incidence of diet-related chronic diseases is higher than it’s ever been. This is clear proof, they say, that existing diets don’t work. Except it isn’t. For if all currently existing diets were ineffective in producing good health, then everyone would be unhealthy. But while most American adults are fat and doomed to die from heart disease, diabetes, or another disease affected by diet (Alzheimer’s, some cancers), in absolute numbers there are lots of healthy people. Indeed, virtually everyone who actually makes an honest effort to eat healthy by any definition and sustains this effort throughout life is rewarded with robust health. The people who end up fat and saddled with chronic disease are the majority that doesn’t even try to eat healthy.
If we look at the small sliver of the population that sustains its efforts to eat healthy, we find that many existing diets work perfectly well. People who start and stay on sensible versions of vegetarian, Mediterranean, low-carb, low-fat, clean-eating, locavorian, agnostic, and other diets are typically hale and hearty. The problem is not, as the inventors of new diets assert, that there are no good options. The problem is that only a tiny fraction of us takes advantage of the many good options available to us.
Here’s another way to look at it: In 1950, virtually no one was following anything we would recognize as a microbiome diet or a gluten-free diet or a Paleo diet or a high-fat/low-carb (HFLC) diet because A) these diets hadn’t been invented yet and B) they are not culturally normal, so it was unlikely that some random weirdo would eat by the rules of any of them accidentally. Thus, to argue that any of these new diets is needed because no previously existing diet was good enough is essentially to argue that no one living in 1950 was healthy.
Of course, advocates of the Paleo diet argue that their way of eating is not new at all but a reversion to “the original human diet,” and some proponents of the HFLC diet do the same. This argument represents a complete inversion of the truth. Paleo dieters eat the same modern foods that everyone else eats, all of which are only distantly related to the foods eaten by Paleolithic humans. The only difference between the way the average Paleo dieter eats and the way his next door neighbor eats is that the Paleo dieter eschews some foods, such as dairy, that his neighbor eats. This combination of modern foods and selective exclusions is fundamentally novel. When Loren Cordain published The Paleo Diet in 2002, the eating program unveiled therein was the world’s newest diet. If it resembled primitive diets more than other modern diets did, it was only on the most superficial level.
In any case, a more important way in which Paleo diet doctrine stretches credulity is the same way that most other new diets do. According to Paleo doctrine, humans stopped eating right at the dawn of the agricultural revolution some 12,000 years ago. Therefore, to argue that the Paleo diet is needed because no post-Paleolithic diet was good enough to support optimal health is essentially to argue that there have been no healthy humans for the past 12 millennia.
Let me be clear: I’m not suggesting that all new diets are bad. I think most of them are good. Humans can thrive on a wide range of diets, so it’s not hard to come up with a novel diet that respects the few nutritional laws that can’t be broken without repercussions for health. But no new diets are needed. The current epidemic of diet-related diseases will not be solved by the discovery of the first and only diet that really works. Good-enough diets have always been available. Until scientists invent a pill that makes people crave broccoli and gag at the sight of french fries, each of us is on his own to solve the problem individually by selecting one of the many good-enough diets and sticking with it.
Most popular weight-loss diets keep lists of forbidden foods—foods you must not eat. Ever. Low-fat diet gurus say we must not eat any high-fat foods if we hope to get leaner. No bacon, no cheese, no oil-based salad dressing. Glycemic control diet gurus say we must not eat any high-glycemic foods or else we’ll never reach our goal weight. No peaches, no potatoes, no pasta. And so forth.
A reality check indicates that such forbidden food lists are both longer than they really need to be and too narrowly defined. In my view, a food should not be forbidden to dieters unless it meets two criteria: 1) it is eaten most frequently by the fattest people and least often by the leanest and 2) its consumption is associated with significant long-term weight gain. Not all high-fat foods or high-glycemic foods or high-whatever foods meet these criteria. Only four foods do: fast food, soft drinks, fried food, and snack chips.
Hamburgers and French fries purchased from fast food restaurants may be the biggest individual food contributors to weight gain in America. The average American gets 11.3 percent of his or her calories from fast food. But normal-weight persons tend to eat less fast food while fat people eat more. For every 100 calories a normal-weight American gets from fast food, an obese American gets 125.
Longitudinal research demonstrates that this association is not coincidental but causal. A 2005 study from the University of Minnesota reported that, over a 15-year period, people who ate fast food two or more times per week gained 10 more pounds than did people who ate fast food less than once a week.
Most fast foods have a very high fat content. A Burger King Whopper contains 37 grams of fat and gets 333 of its 650 calories from fat. A medium order of french fries at Burger King contains 18 grams of fat and gets 162 of its 410 calories from fat. It would be a mistake, however, to caution against eating high-fat foods in general rather than fast food specifically. After all, nuts and yogurt are high in fat, but people who eat lots of these foods tend to be slimmer than those who eat less of them.
It would also be a mistake to steer weight-loss seekers away from only high-fat fast foods. There are low-fat foods that are just as fattening—or one, anyway: soft drinks. Adults who drink at least on soda per day are 27 percent more likely to be overweight or obese than are those who never drink soda. As you know, all of the calories in most soft drinks come from sugar. But it would be a mistake to caution dieters against consuming all foods high in sugar. Many fruits are high in sugar, but people who eat lots of fruit are leaner than those who eat little fruit.
In fact, it’s not even necessary to include candy on a list of foods forbidden to the weight-loss seeker. Fat people do not eat more candy than the general population. Because candy is energy dense and not terribly satiating, in principle it has the potential to be quite fattening. But in practice candy is seldom the main culprit in individual cases of weight gain because candy doesn’t invite gorging the way fast food meals do. People routinely consume 1,000-plus calories of fast food in a single sitting. People do not routinely eat four and a half bags (i.e. 1,000 calories’ worth) of Skittles in a single sitting, or even in a single day.
Fried foods and snack chips, on the other hand, are even more energy dense and even less satiating than candy and they do tend to be eaten in larger amounts. Unlike candy, fried foods and snack chips are eaten most frequently by the fattest people and therefore they are much better candidates for inclusion on our sensible lost of foods forbidden to the weight-loss seeker.
A 2013 study by Spanish researchers found that, within a population of 9,850 adult males, those who ate fried food four or more times per week were 37 percent more likely to be overweight or obese than were those who ate fried food two or fewer times per week. A well-known 2011 study from the Harvard School of Public Health found that potato chips were associated with more weight gain in a population of nearly 120,000 American adults over a 20-year period than was any other food or food type. Doritos and other snack chips were not looked at in this particular study, but I’m confident they have similar effects.
There are many successful dieters—not to mention people who have never been overweight—who don’t forbid themselves anything. They just don’t eat much of whichever foods they consider most fattening. I am one such person, and there are no forbidden foods in the “agnostic healthy eating” approach I recommend to others. But I’m aware that declaring certain foods completely off limits works for some people. If you belong to this psychological type—if you insist on not eating certain foods—then I encourage you to select these four: fast food, soft drinks, fried food, and snack chips.
There are plenty of items not on this list that you should not eat often—e.g. sweets, refined grains, processed meats—but both real-world and scientific evidence suggest that complete abstinence from these foods won’t aid your weight-loss efforts any more than moderation. As eaters, it’s easier for us to say “yes” than “no.” So keep your “no’s” to a minimum. If you can avoid fast food, soft drinks, fried food, and snack chips for the rest of your life without going crazy, great. But focus the rest of your attention on saying “yes” to foods that make you leaner when you eat more of them, such as vegetables, fruit, nuts and seeds, whole grains, yogurt, and fish.
Everyone knows Aesop’s fable about the fox and the grapes. A fox is walking along in the forest when he spots a juicy bunch of grapes hanging from a branch. He leaps upward and tries to snatch the fruit between his teeth but he misses. He tries a second time and misses again. After a third miss he gives up and slinks away, muttering, “They’re probably sour anyway.”
Psychologists have a term for what the fox was experiencing: cognitive dissonance. The term refers to any situation where reality contradicts one’s preferred self-conception. The natural response to such situations is to change one’s beliefs about reality in such a way as to preserve one’s self-conception. In Aesop’s fable, the fox decided he never wanted the grapes in the first place so that he would not have to admit he couldn’t jump high enough to get them.
There is an epidemic of “sour grapes syndrome” (as I call it) in endurance sports today. Its victims are endurance athletes who cannot cope psychologically with being slower than they would like to be and who resolve this cognitive dissonance by replacing the goal of doing their sport well with that of doing it “right.” The syndrome is being spread by various movements that promote alternative methods that are contrary to those practiced by the most successful athletes. Examples include barefoot running, interval-based training, and high-fat diets.
By latching onto one of these methods, athletes can claim a kind of victory over superior competitors. “You may have finished the race ahead of me, but you were heel striking whereas I was forefoot striking, and since the real objective of racing is not to finish as quickly as possible but to exhibit the best form, I actually beat you.” That sort of thing.
It sounds infantile—and it is—but it’s a widespread mentality. I hasten to add, though, that the vast majority of slower endurance athletes are perfectly okay with being slow. They are focused on improving their own best times and couldn’t care less how many people finish in front of them. It’s only a small minority that is eaten alive by its slowness to such a degree that it feels compelled to change the rules of the game. Interestingly, but not surprisingly, most endurance athletes who suffer from sour grapes syndrome are male.
Elite athletes never go in for the alternative methods, for a couple of reasons. The first is obvious: As the fastest athletes, the elites do not experience the gnawing envy of faster athletes that is at the heart of sour grapes syndrome. The second reason is that the alternative methods don’t work as well as the dominant best practices. Athletes whose livelihood depends on being as fast as possible can’t afford to fool around with inferior methods the way slower athletes with alternative goals can.
I try not to judge athletes with sour grapes syndrome, but I do feel compelled to speak up when a particular movement becomes visible enough that it begins to win converts among athletes who are not, in fact, wracked with jealousy of faster athletes but who simply don’t know any better. There are signs that the high-fat/low-carb diet trend has passed this tipping point. I’m hearing from more and more athletes whose training has been ruined by a switch to a HFLC diet that was precipitated by an earnest wish do get faster and not by a desire to have something to hold over faster athletes who eat lots of carbs.
So I’m standing on my soapbox and putting a bullhorn to my lips to spread the message that HFLC diets are not good for most endurance athletes. They reduce tolerance for high-intensity training and impair performance in all races except perhaps ultra-endurance events such as 100 km trail runs.
The latest scientific proof of this already well-proven fact comes from a new study published in the journal Nutrients. Polish researchers placed eight mountain bikers on each of two diets for four weeks in random order. One diet was high in fat and low in carbohydrate, consisting of 15 percent carbohydrate, 70 percent fat, and 15 percent protein. The other diet was balanced, consisting of 50 percent carbohydrate, 30 percent fat, and 20 percent protein. At the end of each dietary intervention, the subjects underwent three days of physiological testing that culminated in a 90-minute stationary bike ride at 85 percent of lactate threshold power followed by a 15-minute time trial.
Before I share the results, let me pause to note that the founding principle of HFLC diets for athletes is that carbohydrate does nothing good for the body either at rest or in motion. Proponents of these diets believe not only that eating carbohydrate is fattening and otherwise unhealthy, but also that burning carbohydrate during exercise hurts performance by hastening exhaustion. The rationale for prescribing HFLC diets for endurance athletes is that they increase the reliance of the muscles of fat and decrease their reliance on carbohydrate, thereby enhancing performance.
The Polish researchers who conducted the study in question found that the HFLC diet did everything it was supposed to do physiologically. For starters, it made the subjects leaner. After four weeks on the balanced diet, the subjects’ average body fat percentage was 14.88. After four weeks on the HFLC diet it was 11.02. The HFLC diet also increased fat burning during exercise. Scientists use a measure called respiratory exchange ratio (RER) to quantify the relative contributions of fat burning and carbohydrate burning to muscle work. The higher the number, the more carbs are being burned relative to fat. On average, the subjects’ RER during exercise was 6 percent lower on the HFLC diet than on the balanced diet.
There was only one problem. All of these “favorable” physiological changes were associated with a significant loss of performance. On the balanced diet, the subjects generated 257 watts at lactate threshold intensity and 362 watts during the 15-minute maximal effort. On the HFLC diet, these numbers dropped to 246 watts and 350 watts. According to the study authors, the cause of the loss of performance capacity on the HFLC diet was impairment of the muscles’ ability to burn carbs. Oops!
So that’s the science. But what about all those social media testimonials you see from athletes who have made the jump to HFLC diets? Let me answer this question by asking another: How many times have you seen testimonials for weight-loss pills and muscle-building supplements that don’t really work? I’m not one to dismiss all anecdotal evidence out of hand, but when anecdotal evidence contradicts the results of formal scientific inquiry, it should be given very little weight.
When the barefoot running fad was raging a few years back, many runners who ditched their Brooks Beasts for Vibram Five Fingers reported that going natural had made them better runners. But I never encountered a single barefoot runner who, when pressed, could point to a big new PR that was set soon after the switch. It became clear to me that what these runners really meant when they said that barefoot running made them better was that it hadn’t made them worse.
I do believe there is a minority of endurance athletes who don’t get worse on HFLC diets. I don’t believe there are any who get better. And I believe that most runners who try HFLC diets don’t really do it for the sake of improving, although they convince themselves otherwise. If you really care about your performance, don’t go on a high-fat/low-carb diet… or run barefoot, or switch to an interval-based training approach, or do anything else that race winners don’t do.
Meredith Kessler took an unusual path to the top of the sport of triathlon, competing as an amateur for many years while working full-time in downtown San Francisco before finally turning pro in 2010 at age 31. Since then she has won a number of big races, including Ironman Canada (2010), Ironman Coeur d’Alene (2012), Ironman New Zealand (2012, 2013, 2014), and Ironman 70.3 St. George (2012, 2013, 2014). She also earned a bronze medal at the 2011 ITU Long Distance World Championships and finished seventh at the Ironman World Championship in Hawaii last year.
Coached by Matt Dixon of Purplepatch Fitness, Kessler coaches a handful of athletes herself under the PPF umbrella and teaches spin classes at Shift in San Francisco. Learn more about her here and follow her on Twitter.
What is your racing weight?
My typical racing weight is about 130 lbs, however, this will organically fluctuate, hopefully downward a little, as Kona rolls around!
What are your personal dietary “rules”?
I would have to say that I typically don’t focus in on any personal dietary rules, meaning I generally consume most foods. One rule I do adhere to is that everything is fine in moderation—variety is king—meaning I can have that piece of dark chocolate after dinner yet not 10 pieces. I can eat that cheesy appetizer at dinner yet no need to gorge myself. This allows the mind to stay sane and prevents any potential cravings.
In addition, I eat when I’m hungry and I don’t eat when I’m not—I have always been like this and often for my profession, this isn’t always the best mindset. For example, most of us aren’t extremely hungry (myself included) after a tough workout. Yet it is most important to really eat in that fueling window within 15-20 minutes post workout. I have tried to be better about getting that protein-packed recovery shake or that Greek yogurt in as soon as possible, whether I am ‘hungry’ for it or not. I am well aware that by doing so, it aids in proper recovery in repairing the muscles and providing needed fuel.
Also, I aim to drink 1 oz of water for every lb I weigh, so usually 130 oz (not inclusive of what I have during training sessions) a day as much as I can muster, not all of which is just plain water. I drink 12 oz of water with a packet of emergen-C in it every morning when I first wake up. I drink a LOT of sparkling water (sometimes with a hint of OJ in it) because I find chugging carbonated water so much more satisfying!
What’s a typical breakfast for you?
A typical breakfast is Fage yogurt topped with blueberries, raspberries, a banana and Bungalow Munch granola. After a workout, I usually eat four scrambled eggs with sliced avocado on top, toast (or Van’s waffles) with almond butter and maman raspberry preserve jam, and sometimes more Greek yogurt. As I mentioned previously, this should be consumed in the fueling window as much as possible. I diagram this in extensive detail in my upcoming manuals, Life of a Triathlete.
A typical lunch?
A typical lunch (sometimes the egg meal is the lunch) would be a smoked turkey panini with a slice of pepperjack cheese, pickles, avocado, hummus and carrots and a handful of almonds. Usually a protein shake too is consumed between breakfast and lunch right after the first or second session of the day.
A typical dinner?
We eat a lot of salmon in our household. My husband makes a mean miso marinade and grills the salmon on cedar planks, which tastes amazing. We usually have this with a sweet potato, brown rice mixture or quinoa salad dish as well as a house salad with all the toppings and our homemade salad dressings we like to make. Of course, I would follow up this meal with two pieces of dark chocolate.
What’s the biggest change you’ve made to your diet since college?
The biggest change I have made to my diet since college is keeping everything fairly even throughout breakfast, lunch and snacking. While I may not deviate too much from my staples, I still stand by variety and moderation. Dinner is where I do get a little bit more adventurous so that my diet doesn’t get too predictable and boring.
I have to say, my weight is pretty much the same 365 days a year—whether I’m racing or not racing, training more or training less. Could I trim the fat more especially when racing? Absolutely. Yet then I personally feel that I would be sacrificing (a word I do not like to use in terms of my profession) “life” things that I’m not willing to sacrifice as it’s important to me to be able to celebrate normal life things with my friends and family regardless of what I do for a living. This includes pizza night with the girls, date nights with my husband pairing wine with food, having that cupcake at a two-year-old’s birthday party, and so on, and in December, October or June I like to keep things consistent in this capacity. Again: Everything in moderation. The second I make things complicated in terms of nutrition is when I start to perform poorly in races. I like to also go by feel—I feel happier when I don’t worry about a specific race weight number, and being a happy racer is what fuels me to the finish.