Fats? Carbohydrates? Protein? It’s hard to tell what I’m supposed to eat anymore, because the recommendations seem to change every few years. Jerome Groopman does an excellent job of reconciling the confusion…or, at least, politely explaining that none of the answers are definitive, yet.
Science is an accretion of provisional certainties. Current research includes much that is genuinely promising—several groups have identified genes that predispose some people to obesity, and are studying how targeted diets and exercise can attenuate these effects—but the more one pays attention to the latest news from the labs the harder it becomes to separate signal from noise. Amid the constant back-and-forth of various hypotheses, orthodoxies, and fads, it’s more important to pay attention to the gradual advances, such as our understanding of calories and vitamins or the consensus among studies showing that trans fats exacerbate cardiovascular disease. What this means for most of us is that common sense should prevail. Eat and exercise in moderation; maintain a diet consisting of balanced amounts of protein, fat, and carbohydrates; make sure you get plenty of fruit and vegetables. And enjoy an occasional slice of chocolate cake.
I would add, though, that there won’t necessarily ever be an answer. Your physiological response to food is a product of your genetics, your fetal environment, your early childhood exposure, and your overall nutritional history, which means that everyone will have a unique set of needs and reactions. But moderation and a balanced diet sounds like a safe approach — just pay attention to what your body is telling you. If you feel dizzy and hyper and experience stomach distress when you eat that slice of chocolate cake, stop eating it.