En español | You've done all the right things: dieted, exercised, maybe even tried a cleanse or two. And maybe you've been successful in losing some weight, but not as much as you'd hoped. Sure, you can blame it on a slowing metabolism and shifting hormones, though truthfully, haven't you always suspected there's more to it than that?
We have, too, which is why we parsed the scientific literature to see if there might be other reasons so many people over 50 can't seem to lose the extra pounds. We found five possible culprits — but thankfully, we also found a few simple ways to increase your odds of losing weight.
Maybe it's your meds
Almost half of Americans took at least one prescription medication in the past 30 days, and a side effect of many of those medicines is significant weight gain. Antihistamines, for instance, target a receptor involved with both allergies and appetite; suppressing the receptor's activity can make you hungrier. In one study, men taking certain prescription antihistamines were 21 pounds heavier, and women were 10 pounds heavier, on average, than those who didn't take the drugs. Other drug classes that can cause weight gain include antidepressants, -beta-blockers diabetes medications, corticosteroids and antipsychotic drugs.
Don't quit taking medications you need. Instead, ask your doc for options. Some alternative drugs, such as the antidepressant bupropion and the diabetes drug metformin, may even be associated with weight loss.
Are you sleeping enough?
Lack of sleep can do more than make you cranky; it could also be thwarting your best weight-loss efforts. In one recent study, adults who got just 41/2 hours of sleep for four nights straight ate significantly more than they usually did. In another study of older adults, regularly getting five hours of sleep instead of seven or eight tripled obesity risks in men and doubled them in women. About a third of Americans get less than six hours of shut-eye a night, according to the Centers for Disease Control and Prevention — and about a third are obese.
Establish a healthy sleep routine. Aim to get seven or eight hours every night, and stick to a schedule in which you go to bed and get up at the same times each day — even on the weekends. That helps regulate sleep-wake cycles and other body rhythms, including your appetite.
Your gut could be the cause
Bacteria in the gastrointestinal tract do a world of good — breaking down food, absorbing water and nutrients, regulating insulin sensitivity and producing fuel for cells. Now new research suggests that gut bacteria may also help regulate your weight. In one recent study, germ-free mice got fatter when researchers populated their guts with bugs from obese people, but identical mice eating the same diet stayed lean if they received bacteria from thin people. "There are a lot of different pathways for bacteria to cause obesity, and we're trying to figure out which are important," says Rob Knight, director of the Center for Microbiome Innovation at the University of California, San Diego. Among the possibilities: Certain strains of bacteria may help regulate inflammation, fat metabolism and appetite.
Pause whenever your doctor prescribes an antibiotic, which wipes out wide swaths of bacteria, both good and bad. "Ask 'How important is it to take this, and what would be the consequences if I don't?' " Knight advises. Meanwhile, nurture helpful microbes by eating live-culture (or probiotic) yogurt and high-fiber foods such as broccoli, raspberries and whole grains. But don't limit your diet to favorites: A variety may be more important to your gut than any one food.
Your house might be too comfortable
Any livestock farmer will tell you that animals fatten up faster at Goldilocks temperatures — not too hot and not too cold, a range known as the thermoneutral zone. Humans aren't too different, and most of us strive to go thermoneutral while indoors, where we spend a very comfortable 90 percent of our time. But too much comfy-coziness could be hurting our waistlines. Researchers recently discovered that as temperatures dip, white fat starts behaving like brown fat — a specialized type of fat that burns calories rather than stores them. "We'd studied white fat for years before simply asking if there was a difference between how it functioned in summer and winter," says Philip A. Kern, M.D., director of the Center for Clinical and Translational Science at the University of Kentucky, Lexington.
Bump your thermostat lower. One small study found that being exposed to 10 hours of 66-degree temps each night for a month boosted participants' fat-metabolic activity by 10 percent.
Have you been sick lately?
A certain strain of the common cold called human adenovirus 36 could be making you fat as well as sick. Animals infected with the virus gain significant weight in lab studies, and signs of adenovirus 36 show up more often in people who are obese than in those who are thin. "We've found that 30 percent of obese people have been infected, but only 11 percent of lean people have," says Richard Atkinson, M.D., emeritus professor of medicine and nutritional sciences at the University of Wisconsin, Madison. The virus appears to flood cells with glucose while turning on an enzyme that converts sugar to fat. Based on animal findings, Atkinson speculates that the virus could boost weight by as much as 12 to 15 percent.
Dodge adenovirus 36 the same way you avoid other cold germs — by washing your hands frequently; avoiding touching your nose, eyes or face (especially after shaking hands or coming in contact with someone who is sick); exercising to boost your immune system; and getting enough rest.