When people see labels or menus listing the calories in their food, it doesn't change their consumption in any way beyond what experts call "statistical wobble." About two fewer almonds worth of calories per meal. But two almonds over time can add up to a lot.
That's the conclusion in the data of a systematic review by The Cochrane Collaboration. The team of academics reviewed 25 papers which discussed the impact of calorie labeling on consumption and found a minute reduction in the foods selected - about 11 calories.
So few calories an hour of chewing gum will burn it off. Or one minute of exercise. If you are the type of person to 'gamify' life, finding 11 calories per meal can even be fun. Yet critics rightly argue the added cost of more labels isn't worth it if 11 calories per meal is the impact. That is true, we can't lament the 44% food inflation the poor have been subjected to over the last four years and then make food more expensive with gimmicks that don't work.
Except they might. Historical data show that nearly 90% of people ages 20 to 40 will add 20 lbs. of weight in the next 10 years. The rule of thumb is that it takes eating 3,500 calories more than you burn to gain a pound in weight. So 33 calories per day less would mean not gaining 3 pounds per year. Over 10 years you'd stay svelte while your friends punched new holes in their belts.
If you can burn off 11 calories by chewing gum for a long time, that means you can also mitigate it with just three minutes of exercise. Or not eat the calories at all. For people who drink alcohol, it could be even easier. It is one less beer per week, no exercise needed.
The analysis had over 10,000 participants from high-income countries and 16 of the papers reviewed used behavior in restaurants, cafeterias, and supermarkets. “Our previous version of this review from 2018 reported a potentially larger effect, but was inconclusive because there was significant uncertainty over the results. This update has reduced that uncertainty, and we can now say with confidence that there is very likely a real, albeit modest, effect,” says senior author Dr Gareth Hollands from the UCL Social Research Institute.
