Correction: An earlier version of this story mischaracterized the hormone ghrelin, which was monitored in a study in the journal eLife. The hormone signals hunger, not fullness, and rose, as opposed to plummeting, when rats’ meal times were limited. This version has been corrected.


This month, nearly half of all Americans resolved to make 2016 the year they get fitter, faster and reach their feel-great weights. Indeed, weight loss and exercising continue to be among the most popular New Year’s vows, according to a Marist Poll.

It would be wonderful if the pounds melted off as soon as we ramped up our workouts and swore off sweets.

But many people find that weight loss isn’t that simple or linear.

They get stuck in a weight-watching purgatory — dragging themselves through workouts and scrutinizing food labels — while the numbers on the bathroom scale stall or inch upward.

“I hear people say this all the time,” says Tom McGlynn, founder of Runcoach, which trains 1,500 area runners annually for the Marine Corps Marathon, Historic Half Marathon and Cherry Blossom 10-Miler.

To be sure, some of the initial weight gain is often due to water retention, says Jim White, a Virginia Beach-based dietitian and exercise physiologist.

When you lift weights or run up a hill, the muscle fibers tear. The body responds by producing fluids full of white blood cells and nutrients to heal those fibers so you get stronger, says White.

But for more people, the forces that drive the weight gain are much more complex. Here are some common weight-loss traps and how to avoid them.

You do too much too­­ soon

Many people try to overhaul their diets while simultaneously logging monster workout sessions at a pace that’s unsustainable. “People get all excited about counting calories, they overexercise and undereat, and it ends up being too much restriction,” says exercise physiologist Jenny Hadfield. “Three weeks after they start, they can’t manage it, and the scale tips the other way.” Without adequate fueling, workouts become a waste of time; with no energy to push their bodies faster, harder and longer, people can’t make substantial fitness gains.

And the body rebels, Hadfield says. “When we drastically reduce calorie consumption and combine that with higher levels of exercise, the body adapts by lowering our metabolic rates.” You may drop pounds at first, but eventually you regain the weight, and then some. There’s also new evidence that excess restriction messes with the body’s hunger mechanism. In a study published in the December issue of the journal eLife, when rats’ meal times were limited, levels of the hunger hormone ghrelin rose and they ate twice as much.

Hadfield says baby steps are often more effective. With exercise, do a variety of workouts: short, easy aerobic efforts, endurance-building long sessions, strength and cross-training. Make one to two small dietary changes at a time, and give yourself time to adjust to each change before making another. “Even just a glass of wine can be the difference between maintaining and losing weight,” says White. But don’t get rid of the pre-workout nosh. White recommends eating a snack of 100 calories 30 minutes before exercise — say a piece of fruit, a cup of yogurt or half a granola bar. “You just don’t want to be hungry, as that can cause you to be weak,” he says. Experiment with different foods to figure out what gives you a boost without upsetting your stomach.

You adopt a diet off the shelf

Many people hitch their weight-loss hopes to a popular diet, declaring themselves low-carb, paleo or gluten-free without considering their own likes and lifestyles. If a diet requires consuming specialty foods that drain your wallet or make you feel chronically deprived, it isn’t likely to last. “One-size-fits-all programs can be effective in the short term,” says White, “but they can be too hard to follow, and people often end up gaining weight back.” Adopt an eating plan that you can afford and enjoy, and allow yourself a weekly treat meal. Just don’t regard it as a “cheat” meal, White warns, which perpetuates a fear-based attitude about food. Indeed, research suggests that the idea of cheating can derail your diet. In a study published in the March 2014 issue of Appetite, people who associated chocolate cake with guilt reported less control over eating and were less successful at weight loss compared with those who associated the cake with celebration.

Your eating and exercise habits don’t work

Any diet must support your exercise routine so you get adequate amounts of nutrients. Coaches say they see a lot of people attempting low-carb diets while training for endurance events such as marathons, and that often backfires. Carbs are the nutrient the body can most efficiently convert into energy. So trying to exercise without carbs “is like trying to drive your car with zero gas,” White says. “People go to exercise, they have no energy, they hate it and get discouraged.” Once you pick a workout routine or a sports goal, meet with a dietitian to customize an eating plan that will complement it.

You go overboard with the energy bars

Grocery shelves are packed with sports bars that promise to deliver speed, strength and energy. Snack, nutrition and protein bars have become a $6.2 billion market, according to Mintel, a Chicago research firm. And sales of performance bars geared to enhancing fitness and exercise have skyrocketed by 83 percent since 2009. Many of these products have calorie, sugar and fat profiles that rival conventional candy bars. Though these foods are designed for refueling during workouts of 60 minutes or longer, many people go overboard once they start working out. “People eat those products and figure, ‘That wasn’t real food. Now I have to go get a real meal,’ ” McGlynn says. “Meanwhile, they just ate 500 calories.” He encourages clients to focus on fruits, vegetables and grains for carbs; poultry, fish and lean red meat for protein; and nuts and avocados for fats. “Spend the calories on natural foods that we know have vitamins and nutrients that are beneficial,” he says.

You overcompensate for calorie burn

Many people find that the more they exercise, the more they eat, either because the increased activity makes them hungrier or because they feel entitled to a doughnut after a tough workout. In a study published in the May 2014 issue of Marketing Letters, people who were told a two-kilometer walk was exercise ate 35 percent more chocolate pudding afterward than those who thought the same stroll was a “scenic walk.” And it takes only minutes to eat back the calories burned on a 30-minute run. To avoid this, before your workout, prepare a post-workout snack that you can grab when you return — say some fat-free Greek yogurt and a piece of fruit, or some rice cakes with peanut butter. And find ways to make your calorie burn fun. Meet a friend for a run so your workout becomes a social hour. Download audiobooks and reserve your exercise time for entertainment. Most important, find a form of exercise that you genuinely enjoy. Because you dread it, you’re not going to do it.

More from Wellness:

Why running for time, not distance, can help in endurance training

What happens when you send a ‘Star Wars’ superfan to a lightsaber workout class

After losing 200 pounds, app creator aims to turn monotonous exercise into fun

Jennifer Van Allen is the co-author of “Run to Lose: A Complete Guide to Weight Loss for Runners” with dietitian Pamela Nisevich Bede.