I used to be guilty of looking askance at fat people, sharing the common idea that they just overeat. While that may sometimes be true, I’ve increasingly learned how obesity is more an affliction than a failing.

An evolutionary maladaptation — modernity is an environment different from what we evolved to cope with, one of Food scarcity, and “feast or famine.” Programming us, genetically, to eat as much as possible when food is available, to stockpile calories against lean times. Energy-rich foods like fats and sugars were especially valuable, so we are made to crave them especially. We’re fortunate to live now, instead, in a world of abundance. But it does make many people fat.

Not only do we have more food, but much is “processed food” which, ounce-for-ounce (and perhaps even calorie-for-calorie) causes more weight gain.

Also, people today generally have to work much less hard (another blessing); that lesser physical exertion means fewer calories burned. A study cited in a recent article in The Economist found that between 1960 and 2006, America’s reduction in energy expended averaged 100 calories a day — accounting for much of that period’s weight gain.

Still further, mental health conditions — and some medicines for treating them — add pounds.

And The Economist article noted yet another factor I hadn’t appreciated. Not only are we biologically programmed to eat whenever possible, our bodies monitor our food intake. If it drops, our metabolism slows to compensate, to conserve calories, reducing the rate at which they’re burned.

And thus reducing how much you can eat without weight gain. A study of “Biggest Loser” contestants found that this effect persisted for six years. Making dieting self-defeating.

Still, you might think folks could override their appetites with willpower. But it’s actually a lot harder for some than for others. People differ greatly in their genetics and internal biology, with varying metabolisms, and populations of gut bacteria, which affects how the body processes food. Thus some people are more prone to put on weight, so dieting and exercise work less well to shed it.

Hence our global obesity epidemic. Not only making people less attractive, but less healthy, which in turn has economic impacts, in added health care costs, and working time lost to illness and premature deaths. All together the equivalent, says The Economist, of another Covid pandemic annually.

But science is finally coming to the rescue. Previous weight loss treatments were not silver bullets and tended to have unfortunate side effects. But now, drugs originally developed to combat diabetes have been found to reduce weight —significantly — and with more tolerable side effects. Celebrities in particular have leaped in, some sporting new slim looks.

Ozempic (a/k/a Wegovy) is made by Novo Nordisk; Mounjaro, by Eli Lilly. Both are “GLP-1 agonists” which mimic the hormones the body produces naturally after eating, and also keep food in the stomach longer — thereby curbing appetite. (In fact, if you overeat, you feel sick.) So weight naturally declines.

A downside is that in most cases these drugs will have to be used for life. And they are, for now at least, expensive, hence beyond the reach of the world’s less affluent, who also tend to be the most afflicted by excess weight. (While getting food used to be poor people’s main problem, nowadays the problem is the kind of food they’re able to find and afford.)

But deploying these drugs should provide net savings to humanity in reduced costs for obesity-related health care and greater work productivity. It’s foreseen that these will ultimately become the biggest thing ever in the pharmaceutical universe.

On the other hand, a letter-to-editor in The Economist, responding to its article, observed that these medicines will unfortunately signal people that exercise and eating right is less important. While another said that most obese people really need to lose more weight than these drugs can induce.

A footnote: it’s a known phenomenon that people’s professions echo their names at rates greater than chance. Thus Lawrences are disproportionately apt to be lawyers; and Dennises dentists. And an “obesity researcher” cited in The Economist article is named — Fatima!