The Obesity Code summary

People often intuitively believe that weight loss is all about how much you eat. Reduce your calorie intake, the thinking goes, and your weight will also decrease. Sounds pretty plausible, right? Well, there’s a problem – it’s just not true. In fact, there’s no causal relationship between calorie intake and obesity.

One of the reasons for this misconception is that there’s a correlation between greater calorie intake and higher obesity rates. According to the Mortality and Morbidity Report by Doctors J. D. Wright and J. Kennedy published in 2004, calorie consumption in the United States increased by an average of 250 calories per person per day between 1971 and 2000. But that wasn’t what was causing obesity in the country.

What would happen if you suddenly reduced your calorie intake while continuing to expend the same amount of energy? Well, you’d die! That’s why your body reduces its overall energy expenditure when you eat less.

We’ve known that for a while now. Take a classic study conducted in 1919 at the Carnegie Institute in Washington, D.C. Participants were put on a strict diet and consumed between 1,400 and 2,100 calories a day – a reduction of around 30 percent compared to their usual diets. What the researchers wanted to find out was what effect this would have on their bodies.

Putting on weight is easy. Contrary to popular belief, the most effective way of piling on the pounds isn’t binge eating. If you really want to gain weight rapidly, all you have to do is inject yourself with a hormone which your body already produces: insulin.

And it’s insulin, or rather increased insulin levels and associated hormonal imbalances, that are the main cause of obesity. That’s something L. C. Kong showed in a 2013 study. According to Kong’s research, some 75 percent of all successful weight-loss efforts can be directly attributed to reduced insulin levels. Kong also showed that drugs which raise people’s insulin levels result in weight gains while drugs which have the opposite effect cause weight loss.

Oprah Winfrey has had a very public battle with weight loss. After losing more than 60 pounds in 1988, she started gaining weight again. Since then, she’s experienced something familiar to anyone who’s tried out various diets at some point: an endless cycle of losing and regaining weight. So what makes dieting so hard? Well, it seems that high insulin levels are to blame. Eventually, that leads to insulin resistance. But before we get to that, let’s take a closer look at insulin itself.

Insulin is basically a hormone responsible for removing sugar from your bloodstream and depositing it in your body’s cells, thus regulating your blood sugar levels. When you eat carbohydrates and sugars, the body produces extra insulin to deal with those incoming sugars. Eating too many sugary or carbohydrate-rich foods throws that delicate mechanism out of whack.

In the past, the poorest classes in society were pitied for their thinness, which was understood as a reflection of the fact that they were often malnourished. Over time, thinness came to be seen as a desirable trait. Obesity, by contrast, is now associated with poverty rather than wealth. That’s not just symbolic – there’s a strong correlation between obesity and poverty in contemporary society.

Take the Pima people, Native Americans who primarily live in southwestern American states like Arizona. Their communities are generally very poor, and around 50 percent of all adults suffer from obesity. It wasn’t always that way. According to the historical evidence available to us, it seems that the Pima were fit and healthy agriculturalists and hunters for much of the nineteenth century. Things started to go downhill for them after colonists settled on their land and disrupted their way of life.

As obesity became a recognized public health issue in the second half of the twentieth century, experts and laymen alike reached a seemingly plausible conclusion: people were putting on too much weight because they were eating too much fat. There was just one problem with this theory: it was wrong.

In fact, most dietary fats aren’t unhealthy at all. Despite the widespread assumption that fats were to blame, the evidence that this isn’t the case has been around for a while now. Take a 1948 study conducted by Harvard scientists in the town of Framingham, Massachusetts.

By this point, you might be wondering what all this means in terms of your diet: what should you eat, and which things are best avoided? Well, here’s the main takeaway: the problem isn’t dietary fat – it’s sugar. Cut your sugar consumption, and you’ll also dramatically decrease your risk of obesity. Let’s take a closer look at this devilishly sweet health hazard.

Sugar does a couple of things that make obesity and related issues much more likely: first off, it increases your insulin levels, and that – as we’ve seen – eventually leads to insulin resistance, above all in your liver. That’s down to the fact that sugar or sucrose contains something called fructose, a type of sugar which only the liver can absorb. When you consume too much of this substance, your liver struggles to keep up and begins transforming fructose into fat. That, in turn, increases the risk of insulin resistance and interferes with healthy digestive functions.