14 DAY TRIAL // You ingest a peanut and get fat while the skinny dude in front of you eats five hamburgers and stays just as slim as always...Well, I don't know if it's really "a peanut" that you eat, since quite often you fell like "devastating" a bag of potato chips or a huge chocolate bar and not an apple or an orange.
Does this eating drive get out of control?
Physiologists are increasingly decoding the way our hormones collaborate with our brain and making us helpless. The organism has a physiological mechanism that balances its energy, and "tells" it when it needs food. This is based on the communication between hormones and brain.
This communication can be perturbed by prolonged food shortages, chronic stress, prenatal nutrition, early exercise patterns and other factors. In environments where food is scarce or abundance is seasonal, the brain boosts consumption, especially of high fats and sugars, even when the food supply turns more abundant. That was an adaptive response that helped the body withstand food shortages in initial hunter-gatherers populations; but in today's conditions, the food shortages do not really appear, and the body gets overweight.
Stress can induce the same effect on the brain, boosting the intake of fatty and sugary foods (comfort aliments), triggering a hard-to-combat obesity. The hormones leptin and insulin are involved in stopping obesity development when calories intake rises. They interact with brain receptors, like the hypothalamic arcuate nucleus, to regulate food intake and glucose metabolism.
Recently, researchers discovered that leptin, selectively signaling in that brain nucleus, is enough to decrease food intake and body weight and to increase insulin sensitivity. In some cases, these hormones work well, so that those people do not get fat during bouts of overeating. But when the organism is less sensitive to leptin and insulin, the risk of obesity is high.
It seems that the brain can be scheduled by early-life factors to determine an individual's adult weight, like the womb environment in late pregnancy and the individual's level activity in childhood. These early factors shape the brain pathways of energy homeostasis (balance) and once the tendency to develop obesity at early ages installs, it's impossible to reverse it.
The good news is that factors could be modeled.
Other hormones involved in bodyweight are the glucocorticoids. "Belly fat" is the result of these hormones and insulin and has been linked to many negative health outcomes (heart disease or diabetes) compared to the fat stored in other areas, for example, on the hips.
Glucocorticoids turn on our brain's desire for food, linked to physiological need. During irregular food intake or prolonged stress, glucocorticoids trigger a craving for "comfort" sugar and fat rich aliments. However, the belly fat is also an efficient way of storing energy for eventual shortage periods.