Why Do You Gain Weight When You Exercise and Cut Calories?

You're seemingly doing everything right -- trimming portion sizes and exercising regularly -- but your body just won't let go of excess weight. Before you give up in frustration and believe that you're destined to be overweight, examine your weight-loss strategies to determine if certain adjustments could help you meet your goals. Specific habits and lifestyle traps may be hindering your progress.

Consider if you're truly eating the number of calories you think you are. Unless you weigh and measure your food, you can't be sure you're eating the number of calories necessary for you to lose weight. In general, people tend to under-report what they consume by an average of 30 percent, notes professor Marion Nestle of New York University in a 2012 issue of The Atlantic.

You may also have a better recall of the healthy food habits you've adopted and forget to count the occasional bag of chips, cookie or fancy coffee drink. The free samples at the store, the scraps on your child's plate and the slice of birthday cake at the office all count, and they could be -- literally -- weighing you down.

Under-reporting isn't always your fault -- some calorie declarations on food labels are off by 8 percent and restaurant counts off by 18 percent, according to a 2010 study published in the Journal of the American Dietetic Association. While you can't correct their calculations, you can avoid processed and restaurant foods in favor of whole, home-prepared meals.

Keep a meticulous food diary to monitor your process. If you're deviating from your plan more than you realize, this may prevent you from truly trimming calories to lose weight.

Simply cutting calories doesn't necessarily mean you'll lose weight. You have to make sure that you're reducing them enough to create a calorie deficit for you.

For example, say you need 2,000 calories daily to maintain your weight, and you've regularly been consuming 2,600 calories. You notice the weight increase due to this surplus and thus embark on your diet plan to lose the extra pounds. You cut out 500 calories per day to lose a pound per week, but that means you're still taking in 2,100 calories daily -- which will show as an incremental gain of 0.2 pound per week.

If you're cutting calories, you have to make sure it's by enough to create a deficit for you. Use an online calculator or talk to a dietitian to get an estimate of how many calories you truly need daily to maintain your weight, and then cut 250 to 500 calories from that number to lose 1/2 to 1 pound per week.

Part of your missed calorie calculations may be due to your perception of your physical activity level. A study in PLoS One published in 2014 demonstrated how people largely overestimate their intensity when exercising. While the 129 participants were able to identify a light activity, they misinterpreted moderate and vigorous intensity levels. They identified moderate activity as about 58 percent of maximum heart rate when it's really 64 to 76 percent. And they pegged vigorous intensity at about 69 percent of heart rate max when it's actually 77 to 93 percent.

You simply may think you're burning more calories than you actually are, and this means you may be eating more calories than your body needs. A heart rate monitor can help you determine if you're working in the zone appropriate for you.

Consider whether you're really giving it your all when you do hit the gym. Cutting calories too extremely, below about 1,200 per day, leaves you with minimal energy to work out. Your body may eat into lean muscle mass to use as fuel due to the lack of calories coming in and will be more likely to store anything you do eat as fat to protect you from what it perceives as starvation.

Also notice if you use your workouts as an excuse to skip other activity during the day -- you park closer to your destination, take the elevator rather than climb the stairs or take your kids to a movie instead of playing putt-putt golf. All these small movements contribute to your metabolism -- when you skip them, you may be burning fewer calories than you think all day long and not creating a deficit. Consider a slightly higher calorie intake that keeps you energized so you feel healthy, move more and ultimately lose more weight.

Too little sleep and too much stress can also interfere with your weight-loss efforts. When you don't get a quality seven to nine hours per night, you may rely on calorie-ridden caffeinated drinks to keep you up -- a sugary coffee drink or fizzy energy drink counts toward your daily calorie intake. With too little sleep, the hormones that make you hungry increase while those that make you feel full decrease when you're short on sleep. This can cause you to "cheat" on your diet plan and miss the gym more often than you think, causing weight gain.

Lack of sleep can be caused by stress, which can also result in weight gain. Not only will you crave comfort from sugary, fatty foods, but you also pump out more of the hormone cortisol. This hormone causes you to store more calories as fat, essentially undermining your efforts. Work, bills and family can all contribute to stress, as can low-calorie dieting. A study published in a 2010 issue of Psychosomatic Medicine in 2010 showed that people purposefully restricting their calories experienced greater production of cortisol.