I have lost weight and gained weight and lost it again just to gain it back once more. I have spent summers in the heat swimming, playing baseball, running, losing 20 or more pounds just to gain it back. I always felt like my weight was out of my control (and out of control). With a plethora of weight loss magazines, tips, and America's nationwide obsession with dieting, why don’t diets work?
To begin we need to investigate a hormone: leptin. Leptin targets receptors in the hypothalamus where it inhibits appetite in many ways. The hypothalamus regulates certain metabolic processes such as thirst, sleep, temperature and most importantly, hunger. Leptin inhibits the effects of neuropeptide Y and anandamide, which both stimulate appetite. It also excites the synthesis of an appetite inhibitor. The difference between leptin and other hormones that inhibit appetite, ones that inhibit appetite between meals for instance, is that leptin inhibits appetite in the long term. Regulation of leptin comes full circle and is the heart of the explanation for how leptin regulates weight.
When one loses weight leptin levels decrease. However, the body’s natural response to starvation is higher food intake and lower energy expenditure. This high food intake and low energy expenditure causes weight gain. This is the reason obese and overweight people often cannot keep the weight off: a vicious cycle, which prevents the weight from staying off. The heavier one is, the lower leptin production exists. The lower leptin levels one has, the more one eats, and the cycle continues.
“In humans, diet-induced weight loss results in a decrease in plasma leptin concentration. This may explain the high failure rate of dieting, as low leptin is likely to be a potent stimulus to weight gain,” says Jeffery Friedman in a study at Rockefeller University.
The same goes for countless stars such as Kirstie Allie, and more notably, contestants on The Biggest Loser. Time and time again that once The Biggest Loser winner goes home, and the weight just cannot stay off. The public dismisses this occurrence as a fault on the part of the contestant, as if not enough care was given. In reality, it was the body’s own leptin regulation that caused weight gain.
The lower leptin concentration one has, the heavier they are.
Many forget that as homo sapiens, humans are animals. Friedman goes on to explain, “During starvation, leptin levels fall, thus activating a behavioral, hormonal and metabolic response that is adaptive when food is unavailable.”Every base pair of our DNA is there to contribute to our survival as a race. Leptin regulation is there to ensure that fat stores exist if needed, and to encourage us to seek food if needed.
The question remains: why is it so easy for us to gain the weight back? The answer there lies in marketing and increases in technology and transportation, which have led to a more sedentary society.
The Coca Cola Company spends nearly $3 billion a year on advertising while McDonald's spends a little over $2 billion a year. While we may be obsessed with shows like The Biggest Loser, what are we doing while watching? Remaining sedentary while snacking on the couch. Additionally, availability and portion size of unhealthy food has only increased in recent years.
American culture revolves around food: whether it is the super bowl or summer BBQ’s, large consumption of unhealthy food seems to have been ingrained in our beings. Genetics and environment are against us. What do you do to maintain a healthy lifestyle?