Good Calories, Bad Calories: What Really Makes Us Fat?

Enlarge Image Image Gallery While sugar and soda might be obvious foods to avoid, others such as processed foods, refined carbohydrates and beer should be limited for weight control, as well. KERI ROSEBRAUGH

If you had asked your mother or grandmother for diet tips, you might have heard, “Every woman knows that carbohydrates are fattening.” In fact, that’s from a 1963 article in the British Journal of Nutrition, co-authored by one of the leading nutritionists of the era. And for the previous 100 years or so, this was the conventional wisdom: carbohydrate-rich foods such as bread, potatoes, pasta, rice, sweets and beer make us fat, and, by implication, foods rich in fat and protein do not.

But since then, the nutritional dogma has changed completely, and we’ve come to accept the idea that there is nothing uniquely fattening about carbohydrates. Rather, a calorie is a calorie is a calorie, as nutritionists hasten to tell us. This means that the only way to lose weight is to diligently eat less of everything, to exercise more and hope for the best — a prescription that even the experts will admit rarely seems to work.

As an investigative journalist working in science and health, I’ve spent the last decade assessing the conventional wisdom on diet, weight control and disease. My conclusion is that much of what we’ve been taught since the early 1970s — most of which we’ve all come to accept — is simply wrong. This might explain why those same years have seen unprecedented increases in obesity and diabetes worldwide. When I started my research, I had no idea that I would come to such contrarian views. But now I think that certain conclusions are virtually inescapable:

• Obesity and being overweight are not caused by eating too much and certainly not by eating food with “too much” fat.
• Carbohydrates, not fat, are the cause of excess weight, just as our grandparents’ generation always knew. Eating carbohydrates triggers a hormonal response — insulin secretion — that signals our bodies to accumulate fat. This is why the fewer carbohydrates we consume, the leaner we will be. Sugar, flour and other refined carbohydrates produce an exaggerated version of this response, and so are particularly fattening.
• Exercise doesn’t make us lose weight, it just makes us hungry.
• Dietary fat, whether saturated or not, is not a cause of heart disease. Rather the same foods that make us fat — easily-digestible carbohydrates and sugars — will eventually cause the diseases that are likely to kill us: heart disease, diabetes and even most cancers. As the late Tim Russert’s physician explained in The New York Times shortly after Russert’s death, “if there’s one number that’s a predictor of mortality, it’s waist circumference.” Because carbohydrate-rich foods increase our waist circumference, then it must be these same foods that shorten our lives.