13 Surprising Things That Might Be Making You Gain Weight

From fad diets to late dinners, here's why experts say you might be packing on a few extra pounds.


During food-heavy periods like the holiday season, it's normal to gain a couple extra pounds. What's far less easier to come to terms with is seeing the number on your scale increase even when you're on a diet, hitting the gym, and sticking to a semi-normal sleep schedule. What gives? Well, there are several surprising reasons why you might be gaining weight, some of which are directly related to the very things you're doing to try to lose weight.

Your oral hygiene

Man getting his teeth and gums checked out at the dentist

Your dental health can have a greater influence on your over all physical health than you may think. How? Well, for one, unhealthy gums may can cause you to gain weight!

"There is a direct link between the inflammation that causes gum disease and inflammation in the rest of the body," says dental hygienist Kelly Hancock. "When this inflammatory response spreads to the rest of the body, it can cause the body to store fat. It can also make you tired and stressed, resulting in weight gain." If this doesn't make you start flossing, we don't know what will.

Not eating enough

Watermelon on a plate

Obviously eating too much is a surefire way to gain weight. But did you know that not eating enough can also increase the number on the scale? "If you are not getting enough of the right foods in your diet, you will have trouble losing weight and will even put on some extra protection pounds," says movement specialist and physiologist Fiona Gilbert. "When your body thinks it doesn't have access to food, it holds on to fat in an effort to protect itself."

Eating food directly from the container

Woman eating vanilla ice cream straight from the container

When you don't measure out portion sizes, it's easy to misjudge how much food you're actually eating. And if you're eating things straight from the container, then odds are you're eating way more than you realize.

"The rule of thumb is always to 'plate before palate,'" says Nick Rizzo, fitness research director at RunRepeat.com. "Be mindful of how much you are eating by simply taking whatever snack or food you are eating and putting it on a plate. This way you are actively choosing how much you are eating ahead of time, being mindful about your portions, and are in full control of your calorie consumption."

Indulging in large meals after working out

woman staying up late relaxing at home watching tv and eating pizza

Just because you worked out doesn't mean you can pig out on a crazy, carb-heavy meal. In fact, doing this could be one of the reasons why you're gaining weight instead of losing it.

"The problem here is twofold," says registered nutritionist and weight loss specialist Julie Mancuso. "One: People tend to overestimate the number of calories they burn via exercise. Two: They underestimate the calories ingested via food, especially unhealthy treats. It takes many miles of running to burn off that piece of cheesecake–much more than people think."

The kind of alcohol you drink

Sweet couple having a romantic dinner with wine

It is possible to drink without gaining weight. However, this involves knowing which drinks are OK to consume and which ones you should avoid.

"It is enormously important to educate yourself on healthier alcohol options," Mancuso says. To drink responsibly she says to avoid sugary and creamy mixers, stick to liquors like vodka and gin because they tend to have the fewest calories, and opt for low-sugar wine, which she defines as having less than 10 grams per liter.

Your thyroid

female doctor touching the throat of a patient in the office

Your thyroid plays a big role in the maintenance of your metabolism. And if you have hypothyroidism, or an underactive thyroid, then your metabolism might be slowed down to the point that you're gaining weight. "Having an underactive thyroid can lead to a slower metabolism, which can, and often does, lead to gradual, unsuspecting weight gain," Mancuso says.


A university student of Asian heritage experiencing financial or emotional stress at home in her apartment.

"Anxiety, depression, and other mental health conditions can wreak havoc on our eating habits, which can ultimately lead to weight gain," Mancuso says. In one 2010 study from the University of Alabama at Birmingham, researchers looked at young adults over a 15-year period and found that those who were severely depressed gained weight more rapidly than subjects with well-managed emotions.


Shot of a handsome senior man suffering with a headache at home and looking stressed out

Unfortunately, one of the most common causes of weight gain is stress. "The hormone cortisol can cause weight gain by raising glucose levels via a process called glycogenolysis," says Michael E. Platt, MD, author of Adrenaline Dominance. "Glycogen stored in the liver is converted into glucose. When it comes to sugar, it does not matter if you are eating it or if the body is making it. If you do not burn it up, the body stores the sugar as fat in the fat cells."

Your medications

Mature woman's morning routine - holding medicine and water. Photo of Mature woman with pill and glass of water at home. Mature woman sitting on bed, suffering from depression. Woman takes pill with omega-3 and holding a glass of fresh water.

You know those side effects that drug commercials warn you about? Well, one of the more common ones is weight gain.

"Medications can contribute to an increase in appetite, a reduced metabolism, and other weight-inducing effects," says certified psychiatrist Jared Heathman. If you're worried your medication might be causing you to pack on the pounds, talk to your doctor about trying something with fewer side effects.


Woman lying awake in bed with sleep apnea or insomnia

If you struggle with insomnia, you should talk to your doctor about finding a solution. On top of disrupting your sleep schedule, sleep science and nutrition coach Jason Piper notes that lack of sleep can also lead to weight gain.

"A sleep-deprived person will have higher levels of ghrelin, the hormone that makes you hungry, in their blood, and lower levels of leptin—the hormone that tells you that you feel full," Piper says. "You are going to feel hungrier and eat more because your body is not getting the signal that it is full."

Eating too late at night

Photo from the top of young girl sitting on a bed, eating dinner and watching television

Everyone likes a good late-night snack, but if you're concerned about gaining weight, it's probably best to avoid having one too close to bedtime.

"Eating less than three hours before you lie down doesn't give your body a chance to burn off those calories before it goes into a low-energy sleeping state," says Michael Russo, MD, a bariatric surgeon based in Fountain Valley, California.

Making dinner your largest meal of the day

Woman eating a big unhealthy dinner

If dinner is your biggest meal of the day, that can be just as bad—or worse—as snacking before you hit the hay. A bigger meal tends to mean more calories that your body doesn't have an opportunity to burn, which, Russo says, translates to gaining weight.

In place of a big dinner, try "making your largest meal a high-protein breakfast or lunch instead," he says. "This will allow you to feel more energized throughout the day and allow your body the time to effectively utilize the calories instead of storing them while you sleep."


Man makes a list of healthy food. Healthy lifestyle diet food concept

Ironically, certain restrictive diets can have the exact opposite effect of the one you were hoping for when you chose to go on the diet in the first place.

"Diets tend to make people feel deprived," says clinical psychologist Kimberly M. Daniels, who specializes in disordered eating and obesity. "Once people go off of them, they eat everything they didn't allow themselves before and therefore gain weight." In her practice, Daniels says that she's seen hundreds of women "who have dieted and then regained all of the weight plus additional weight."

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