According to Gary Taubes, the most pressing public health problem facing the world right now is obesity. It was not just concern about the obesity epidemic but also the pervasive misinformation surrounding it that motivated Taubes to write this book. He maintains that the common assumptions about how weight is gained and lost have left millions ill-equipped to manage their weight effectively. In Why We Get Fat, he shows us where the true problem lies, and what we can do about it.

We have grown up hearing from our parents, teachers, and doctors that an energy imbalance is responsible for obesity: we take in more calories than we burn off. The World Health Organization, the U.S. Center for Disease Control, and numerous other health institutes around the world have been saying the same for decades. So why, with all the research and grants and public health recommendations, is obesity on the rise?

Journalist Malcolm Gladwell wrote a piece for The New Yorker in 1998 submitting that the problem lies either with us or with the weight loss advice itself. Gladwell concludes that we are the problem, that most of us lack the discipline to eat less and exercise more. Gladwell was getting at something significant, but he reached the wrong conclusion. The truth is that the common wisdom about weight loss is flawed. It is based on the calories-in/calories-out framework. Unfortunately, there is no panacea. Sacrifice is required to beat obesity, but it is not the sacrifices that journalists, doctors, and politicians have been advocating. The good news is that the actual solution is far more sustainable.

The definition of obesity is not overeating, as some believe; obesity is the accumulation of excess fat. This raises the question: what leads to the accumulation of excess fat? The answer isn’t overeating. Rather, it’s hormones, specifically insulin.

Carbohydrates are the true villains behind obesity. Eating foods that are high in carbohydrates leads to a surge of insulin. When insulin levels are high, the body stores fat instead of burning it. This is not a new development. Before World War II, European scientists at the cutting edge of nutrition research were coming to the same conclusion. But nutrition research got onto the wrong track after the war and never found its way back. It’s hard to shake the misconception that obesity is a calories problem, but we must. 

The benefits of the eat-less/move-more weight loss approach are not evident. Tufts University conducted a review of the weight loss literature from 1980 to 2007 and found that overall the weight loss results obtained in studies were occasionally modest, usually negligible, and never sustainable. Most subjects would gain back any weight lost soon after studies ended. Similar conclusions emerged in the most comprehensive obesity study ever conducted. Harvard teamed up with Pennington Biomedical Research Center to track the progress of 800 obese women—fifty pounds overweight, on average. Subjects were split into four groups, each given varying but balanced portions of fat, protein, and carbohydrates. Subjects were asked to consume 750 fewer calories each day than the average suggested amount. These women were given every edge to help them stay the low-calorie course, like premiere medical counseling and delicious meal plans. Subjects lost an average of nine pounds, but most participants regained that weight within six months.

The few instances of substantial results obtained at university laboratories still face the problem of “now what?” Even if research subjects lose forty pounds each by consuming only 600 calories worth of lean fish and fowl, what is going to happen after the research trial? In all likelihood, they will resume weight gains. Until the 1970s, the under-eating approach was referred to as “semi-starvation.” The method is as unnatural as it sounds, and it is unsustainable. We were not meant to live this way—or lose weight this way.

If exercise is such a beneficial and effective way to lose weight, why are the poor often obese even though they often earn a living by the sweat of their brow? Furthermore, if exercise is an effective path to losing weight, why hasn’t the exercise revolution that has exploded since in the 1970s and 80s eliminated, or at least put a dent in, the obesity rates? As it turns out, the exercise revolution has been outpaced by soaring obesity incidence.

This is why the approach is ineffective: your body will cry out for more calories in order to compensate for the increase in calories expended through more exercise. To embrace the eat-less/move-more paradigm requires one to disregard the obvious phenomenon of “working up an appetite.” It essentially tells us to curb the perfectly natural, healthy impulse to restore the energy deficit. There has got to be an easier way. Somehow the myth that energy disequilibrium is possible and healthy persists, despite almost a century of failing to link eating less and exercising more with losing weight in a convincing manner. 

The belief that eating less and moving more leads to weight loss has led to the conclusion that the obese have no one to blame but themselves for their situation. They are lazy and gluttonous and have failed to cultivate the discipline needed to maintain a healthy weight, and, therefore, are getting their just desserts.

Behavior modification is the championed remedy: if obese people would only start behaving like lean people do, then they would start looking like lean people. This diagnosis is dead wrong, and so is the prescription—it encourages modifying behaviors that have no bearing on weight gain or loss. Misinformation has led to a stigma surrounding obesity.

This misunderstanding has led us to unfairly critique not just individuals but society as well. It is believed that bloated bank accounts have led to bloated bodies. Our prosperity has led to an unhealthy food environment. The logic is that more money means more food, and more food means more calories, and more calories means more weight gain. Of course, this view assumes that calories make the difference. It also fails to account for why plenty of people in a so-called toxic food environment manage to stay lean.

Obesity is not just physiologically harmful, but psychologically damaging to many who have tried and failed to lose weight by following ineffective recommendations.

Carbohydrate cutting is part of any successful diet regimen. What you avoid is far more important to consider than what you do eat. When trying to lose weight, we usually start off by eating different foods: less beer and soda, fewer carbs. We may cut calories, but that matters far less than the carbs that often get cut in the process.

Obviously not everyone who consumes carbohydrates gets fat, but for those who do get fat, carbs—which produce fat storage by spiking insulin levels—are indubitably responsible. This will vary in degrees. The quality and quantity of the carbs consumed, as well as nature and nurture, all impact outcomes. For example, even a mother’s diet while the child is in the womb or nursing will impact the child’s propensity toward obesity. If the mother’s blood sugar levels are consistently high, the pancreas of the unborn or nursing child will generate more insulin-secreting cells, thus making the child more prone to obesity.

It is best to avoid flour, grains, pasta, starches, and liquid carbohydrates like beer, soda, and fruit juices. Unfortunately, many of these items are the cheapest available. This is why obesity and diabetes are serious problems in many poor communities. Even in the developing world, obesity is a problem, as starchy foods like rice and potatoes are common staples in Africa and Asia.

Leafy green vegetables like spinach and kale are excellent for weight loss because they are full of indigestible fiber, which takes a long time to break down and enter the bloodstream. This keeps blood sugar levels low, which means a minimal insulin response. With insulin levels low, the body can burn through its stores of fat.  

Starches like potatoes are densely packed with carbohydrates, which is why they have a more substantial impact on insulin than, say, fruits, which typically have carbohydrates diluted by water. Fruits are not, however, the ultimate weight-loss food. Health experts consider fruits excellent for health because they are fat-free and cholesterol-free (obviously) and free from preservatives, but they do contain fructose. Fructose is the compound in fruit that makes it taste sweet. It is also considered the carbohydrate that is most easily stored as fat. 

Particularly disruptive to the weight-loss process are high fructose corn syrup and sucrose (table sugar). These items are quickly absorbed into the bloodstream and cause a spike in insulin levels. Just because you take your coffee with sugar or have a beer once in a while does not necessarily mean you’ll gain weight, but if you do start gaining excess weight, sugar should be the first thing to go. 

Anyone who took a health class in elementary school is familiar with the food pyramid. Featured in the pyramid’s bottom are carbohydrates: grains, breads, pastas, rice, and so on. This represents what nutritionists recommend as the bulk of any healthy diet. Unfortunately, this is precisely what makes us fat. To argue that carbohydrates lay the foundation for obesity, and not health, flies in the face of basic assumptions about nutrition, and thus receives significant blowback.

Three of the main objections are that carb-restricted diets are scams, they’re imbalanced, and they will lead to heart problems because they are high in dietary fat.

On the face of it, the carb-restricted diet sounds charlatan and detached from reality because it goes against the grain of conventional weight-loss wisdom. How can anyone lose weight without putting in the work of exercise and eating less? These objections that it is too good to be true are based on the calories-in/calories-out paradigm. As mentioned earlier, sacrifice is often required to lose weight or halt weight gain, but it is a different set of sacrifices than conventional wisdom supposes.

The arguments that carb restrictions make for an imbalanced diet are weak as well. Let’s say that you operate from the calories-in/calories-out assumption, and thus cut a quarter or even a third of the calories you usually consume. The cut is even across the dietary board: fats, carbohydrates, proteins are all reduced. By reducing meats and vegetables and eating more carbohydrates than the carb-restricted diet recommends, you would be reducing the foods that actually help weight loss and incorporating more foods that encourage weight gain. That sounds imbalanced. What is more, you would end up fighting persistent hunger. The carb-restricted diet makes far more sense than this semi-starvation model. The food pyramid diet might be popular, but is also imbalanced, miserable, and unsustainable from a weight management perspective.

Another problem with the imbalance argument is that balance is better measured in nutrients that we glean from foods rather than in the food groups themselves. There are no vitamins or amino acids in grains, cereals, and other carbohydrate sources that we couldn’t get from meats, eggs, and leafy green vegetables. Ever since the 1960s, the health researchers decried saturated fat as linked to obesity. Here again, we see that the supposedly imbalanced carb-restricted diet is quite balanced after all, delivering all the nutrients the human body needs to function at an optimal level.

The argument of high-fat diets leading to heart health issues is put forward with the most vehemence. What is well documented is the link between obesity and heart disease; so whatever makes us fat is also making us sick. Despite a growing body of evidence that carbohydrates are the culprits, dietary fat has become vilified, and the belief that saturated fats lead to obesity has become embedded in the public health and nutritionist dogma since the 1970s.

So what are the results of several decades and billions of dollars worth of research and campaigns against dietary fat? Saturated fat consumption has dropped, but we are still getting fatter—not leaner. Moreover, heart disease rates have not decreased, nor have heart attacks. The gap between the accepted assumptions and research results has led to some cognitive dissonance for many in the health field. As is often the case when fundamental beliefs are questioned, many officials and researchers have doubled down and refuse to acknowledge conflicting evidence, but if we truly are serious about confronting this public health issue, the evidence must be examined honestly, not brushed aside.