Beginner’s Guide to Leptin

As a nation, the United States spends more on weight-loss supplements, gym memberships, and programs for weight management than any other country on the planet, and yet, somehow, the US still battles an obesity epidemic. It had gotten so bad, in fact, that Michele Obama launched a program specifically to counter obesity in children. Diet and exercise are, of course, the two most basic ways that a person can manage their weight. The same way accountants have to balance checkbooks, calories in can’t exceed calories out.

In US culture in particular, which continues to propagate strong individualism a la the pull-yourself-up-by-your-bootstraps American Dream, citizens have difficulty understanding that sometimes, there are elements beyond their control that affect their weights. While diet and exercise do matter, the human body has other mechanisms that seem to work against reducing its fat stores, from genes to hormones to environment.

In the 1940s and 50s, scientists took special interest in obese laboratory mice. Termed ob/ob mice, these animals had insatiable appetites and ate to the point of mobility loss, diabetes, and often death. After much research, scientists discovered a recessive gene in these mice and associated it with this voracious appetite, although the mechanism was still unknown. In the 1990s, it was confirmed that the ob gene is responsible for the production of Leptin, a hormone that controls appetite. From the greek root lepto meaning “thin,” Leptin was the first discovered fat-derived hormone and its presence signals to the brain that the body has had enough to eat.

A 1995 study demonstrated that in obese humans, ob genes were expressed more than in fit humans, indicating that there was a problem in the reception of the gene. Leptin insensitivity or resistance became a leading theory in many cases of human obesity. A db gene that codes for leptin receptors was also found to be inhibited in obese mice and humans.

Irregularities in either the production of leptin in the body or the ability to detect its presence can lead to a number of weight issues. Since the hormone is produced by fat itself, issues with the production and reception can lead both to obesity and anorexia depending on whether there’s too much or too little leptin. Since leptin is so influential in weight management, issues with leptin production and reception also influence many other functions, including immune responses, ovulation cycles, blood sugar management, cardiovascular health, and mood.

Often, when an obese person loses a significant amount of weight, their leptin levels plummet to make the body hungrier, as their fat cells become “concerned” about their depleting fat stores. As articulated in a TED talk by Sandra Aamodt, the brain has an idea of how the body is “supposed” to look, so when the body loses a significant amount of weight, while it may be excellent for the person’s health and overall wellbeing, the brain “panics” and tries to put all that weight back on to return to its idea of how the body should look.

In 2014, the USDA approved leptin supplements for those who are incapable of producing their own, and some over-the-counter weight loss supplements claim to contain a synthetic version of the hormone in their recipe.
All the research indicates that fat works against you. Your fat doesn’t want you to either lose or keep off weight, so it toys with your hormones to keep its stores plentiful. It’s not impossible to lose weight and keep it off, but long-term success requires years of re-training your body to cooperate and learn its new eating habits and weight.

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