Anyone that has ever dieted (who hasn't?) knows it is hard, incredibly hard. And at times it can feel like an exercise in futility. And if you have followed all the diet advice to the letter (take in fewer calories than you consume, eat small meals throughout the day, avoid carbs and sugar, exercise daily, don't eat after 7pm, etc. etc.) only to end up frustrated and right back where you started, you are not alone. The fact is, most diets do work. You can lose the weight if you restrict your diet and increase your calorie burn. The problem is keeping it off long term and this is where most diets fail. Unfortunately, scientists are still trying to understand how the body responds to an energy imbalance over time and the knowledge is far from complete.
A new study to be published in the New England Journal of Medicine and profiled in the NYTimes, demonstrates how the body's own hormones work against permanent weight loss. Leptin, a hormone that is directly proportional to the level of body fat, drops dramatically with a significant reduction in body weight (10% of body weight loss in the NEJM study). A decrease in leptin will result in increased appetite and a slower metabolism. Conversely, grehlin, a hormone known to stimulate hunger, increases with weight loss. It makes sense in the context of our need for survival. In hunter-gatherer days, an energy imbalance as a result of going without food for several days would result in the body's hormones kicking in and stimulating the need to hunt for food. This survival mechanism imprinted in our genes is not going to go away just because we live in a modern world with easy access to food in excess supply. The hormonal changes demonstrated in the NEJM study were present one year after weight loss, making the individuals hungrier at their new body weight and essentially ensuring the pounds creep back up.
So our bodies battle against us in the effort to lose weight. This is probably not news to most people struggling valiantly to shed excess pounds. It is time to admit that advising people to diet and change their eating habits is just not enough.
Still going by the advice that if you burn 3500 calories you will lose one pound? If only that nearly universal advice was actually true! To be continued...