We know that calorie-dense, seductive foods like chips, ice cream, and cookies tend to push us to eat too much and gain weight. We also know that being sedentary can expand our waistlines. But there’s another insidious cause of weight gain that many people aren’t aware of: drugs.
‘Wait,’ you may be thinking, ‘I don’t take drugs!’ But chances are you do. Eighty-five per cent of Americans drink a caffeinated beverage every day, and Europeans consume similarly. Eighty-four per cent of Britons and 69 per cent of Americans drink alcohol. Although we consider these habit-forming drugs socially acceptable — within limits — this is a cultural distinction, not a scientific one.
Whether we’re talking about caffeine or crack cocaine, the reason we like habit-forming drugs, and crave them, is that they enter our brains and directly activate motivational circuits that evolved to drive us toward food, sex, water, physical comfort, and other things that were essential to the survival and reproduction of our ancestors. Of course, not all habit-forming drugs are equally potent: crack cocaine does the job more effectively than caffeine, which is why we don’t steal televisions to sell for coffee money.
But just because a drug doesn’t destroy our lives doesn’t mean it has no unwanted side effects. One of the most under-appreciated, yet troubling, side effects of our commonly used drugs is overeating calories. I’ll discuss how this relates to three everyday drugs: alcohol, caffeine, and theobromine.
Alcohol is the most obvious culprit, because the drug itself delivers calories. And the amount is substantial: carbohydrate and protein contain four calories per gram, fat contains nine, and alcohol contains seven. Pure alcohol has a calorie density somewhere between eating crackers and taking a shot of vegetable oil. One typical alcoholic beverage delivers between 90 and 180 calories, with beer and sweet cocktails accounting for the upper end of the range. Two pints of beer is approximately equivalent to the difference in daily calorie intake between a person who is lean and a person who is overweight.
Many of the things we eat and drink contain calories, so what’s so special about alcohol? Couldn’t we make a similar argument about bread or even apples? A key difference between beer and apples is that beer contains a habit-forming drug. Even among people who aren’t addicted to alcohol, we drink it to get the effects of the drug, not because we’re trying to satisfy a need for calories. Because the goal isn’t to satisfy our hunger, we often drink alcohol in addition to the foods we eat, not instead of them. In contrast, we eat apples when we’re hungry and they tend to displace other sources of calories.
Not only does alcohol fail to displace other calories in our diet, it actually drives us to eat additional solid foods. Alcohol stimulates appetite and disinhibits behaviour, which is why you may find yourself in front of an empty basket of chips after a few drinks.
Caffeine is a less obvious example because the drug, and the coffee and tea it comes from, don’t contain any calories. The key to solving this puzzle is to think about what most of us add to our coffee and tea: sugar and dairy. In recent years, fancy coffee drinks have reached obese proportions, delivering up to 500 calories. On its website, Starbucks even offers a list of ‘lighter’ drinks that are under 200 calories — more than a medium-sized baked potato. Many soft drinks also contain caffeine, which contributes to their appeal.
Again, we don’t drink Frappuccinos or soft drinks for the same reason we eat potatoes. We do it in large part because caffeine is a habit-forming drug and we like its effects. This means we often add coffee, tea, soft drinks and the calories they contain on top of what we’re already eating.
Yes, I’m about to tell you the sad truth about your favourite food. Chocolate is the most commonly craved food among women, and it’s frequently craved among men as well. The reason may surprise you. Chocolate is very high in fat and sugar, two properties the brain instinctively loves, but that’s not quite enough to explain why 69,000 square kilometres of cacao plantations blanket the Earth’s tropical regions.
To understand our obsession with chocolate, we have to turn to its chemical constituent theobromine, a habit-forming drug that is a mild stimulant similar to caffeine. Although theobromine on its own may not be the cat’s miaow, when combined with the high fat and sugar content of chocolate, it becomes exceptionally seductive. This means we tend to eat it whether or not we’re hungry — in fact, even if we’re quite full — and this often leads us to overconsume calories.
In an ideal world, we would eat food when we have a genuine need for calories, and stop eating when that need is fulfilled. That’s not the world we live in, and one of the reasons is that our foods and beverages contain habit-forming drugs that drive us to overconsume. Yet most of us don’t want to give up alcohol, coffee, tea, or chocolate. What can we do to mitigate the problem?
Dry wine and spirits contain fewer calories than beer and cocktails, so they deliver more fun per calorie. Yet ultimately all alcohol is high in calories so moderation is the most effective tool. With tea and coffee, the key is to separate the drug from the calories. Black coffee and plain tea are calorie-free, and a splash of milk adds few calories. As far as chocolate is concerned, many people find that their cravings are easier to contain around lower-sugar varieties such as those that contain 80 to 100 per cent cacao. Even if you aren’t the abstemious type, recognising the power of drugs over your eating and drinking and taking steps to mitigate it can help constrain your waistline.
Stephan J Guyenet is the author of The Hungry Brain: Outsmarting the Instincts That Make Us Overeat.