Health / Weight Loss

7 Things That Affect Your Weight (Besides Diet and Exercise)

Three experts go in-depth on each.

There’s nothing quite as perplexing as waking up, stepping on the scale, and seeing an unexpected weight change.

Typically the cause of weight gain or loss is obvious and expected—say, starting a new exercise routine or a series of indulgent meals. If you need help with an exercise routine, check out the Aaptiv app!

But other times the things that affect weight aren’t so clear. When you can’t pinpoint the cause, consider these seven culprits.


The correlation between sleep and weight gain occurs for a handful of reasons. When you don’t get enough sleep and need more energy, you may find yourself reaching for excess amounts of food to provide the necessary fuel.

Amy Shapiro, M.S., R.D., C.D.N., owner of Real Nutrition NYC, explains, “Research shows that the less sleep you get, the more likely you are to store fat and take in more calories. When you are tired, you tend to reach for food or caffeine to keep you going. Because of this, adequate sleep (at least seven and a half hours) is important to maintain weight levels.”

Sleep and Hormones

Lack of sleep also has an impact on your hormones. These can promote weight gain and insulin resistance, says Adrienne Youdim, M.D., F.A.C.P., associate clinical professor of medicine at UCLA.

“Sleep deprivation is associated with obesity and diabetes. In fact, studies show that as little as two days of sleep deprivation is enough to result in hormonal changes that promote weight gain and insulin resistance!” she says. The hormones that regulate your appetite are greatly influenced by how long you sleep. This means a lack of shut-eye causes an increase in appetite that may be excessive to your daily needs.

“Two major hormones control hunger: ghrelin and leptin,” notes Jonathan Valdez, media rep for New York State Academy of Nutrition and Dietetics and owner of Genki Nutrition.

“Ghrelin is a hormone that is released when our body is hungry. It stimulates appetite and promotes fat storage. Leptin has the opposite effect. It suppresses the appetite, telling your body you are not hungry and encourages the body to burn fat. Studies show that those who are sleep deprived may have increased ghrelin levels and decreased leptin levels, causing increased food intake, especially foods high in carbohydrates and sugar.”

This is because of your increase in hunger and a decrease in energy. To ensure a lack of sleep isn’t affecting your hunger level (and many other important functions of the body), prioritize getting at least seven hours of quality sleep.


As if stress weren’t pesky enough, many people are unaware that it has a sneaky effect on weight. “When our stress levels are high, our cortisol (stress hormone) increases. This decreases insulin sensitivity and can cause weight to be stored around our midsection,” Shapiro says.

To be clear, this means that those stress cravings aren’t purely psychological. The decrease in insulin sensitivity—and, therefore, increase in insulin levels—that happens when you’re anxious leads to a drop in blood sugar. This stimulates your appetite, Valdez explains.

Moreover, recent studies are looking into how stress affects weight on a molecular level. “Glucocorticoids, or the body’s natural steroid cells, are produced when the body is trying to fight inflammation,” Valdez says.

“The body’s levels of glucocorticoids naturally rise and fall throughout a 24-hour period. However, if the body is in a constant state of stress during both day and night, glucocorticoid levels are constantly high. As opposed to the usual rise and fall, it causes a higher conversion rate of fat cells than usual.” It’s important to note that more research on this particular reaction is needed.


Chances are, you’ve heard about or experienced a slight weight gain as you get older. Many place responsibility on their metabolism slowing down—and it turns out they aren’t wrong.

“As we age, muscle starts to be replaced with fat. This results in a slower metabolism, which allows the pounds to start packing on,” Youdim says. Many people don’t realize this change in metabolism and continue to eat as they always have. This often leads to weight gain.

“This can become a vicious cycle. As fat cells increase and replace muscle cells, metabolism becomes even lower, increasing weight even more,” Valdez explains.

“Women, specifically around menopause, have a significant decrease in estrogen levels. Estradiol, a specific type of estrogen, has a significant role in metabolism. When it decreases, it changes the ratio of estrogen to testosterone in the body. This change in hormone ratio can lead to a change in fat distribution, causing fat to build up more in the abdomen area as opposed to the hips and thighs.”

In short, as we get older, we may notice that not only are we more prone to weight gain, but the distribution in which we gain it changes, too. There’s no reason to worry—this is completely normal. Simply be aware of your body and habits as you age, and adjust as you see fit.


As if you needed another reason to drink plenty of water, getting too little can impact your weight, as well as tons of important bodily functions. When we don’t get enough water to aid our body is working correctly (for example, with digestion, temperature regulation, and lubrication of the eyes and joints), our cells signal the brain that we need more fluid.

“Sometimes, people can confuse these thirst signals with hunger signals and eat instead of drinking, causing weight gain,” Valdez says. To make sure you’re not confusing the two, always check in with yourself and stay hydrated throughout the day.

On the other hand, drinking plenty of water can cause weight loss. “Studies also show that increased hydration can aid in increased metabolism and increased lipolysis, the process of fat breakdown, aiding in weight loss,” Valdez adds. If you consistently drink a lot of fluids and find yourself having an easier time losing weight, that may be why.


It’s true—a large portion of how and where we gain weight comes down to genetics. In fact, Valdez says that anywhere between 30 and 70 percent of the contribution to being overweight or obese is genetic. “Genes have been found to affect the amount of fat your body stores, as well as the location of stored fat on the body,” he says.

He adds that recent studies are focusing on mutations in certain genes that may cause increased appetite and weight gain. They’ve found that less than 5 percent of the population has a gene mutation that directly causes obesity.

However, other genetic factors have been shown to cause weight gain. This includes if one or both of your parents are overweight and potentially race or ethnicity. The latter has been studied to compare BMI and resting energy expenditure (or calorie burn), Valdez tells us.

“For example, African-American women have shown significantly lower REE levels, as well as lower insulin sensitivity levels than those of Caucasian women. [This] implies certain genetic components for weight and risk for disease,” he explains.


Medications causing weight gain can be a tricky subject, especially because everyone reacts differently to them. Before we get into it, note that everyone’s body is different.

If you’ve gained an unusual amount of weight since starting a medication, consult with your doctor. For some general information, Shapiro informs us, “Some medications can cause carb cravings (like antidepressants) or water retention and bloat. This typically depends on the individual and their response to the medications. Some medications can also simply make it more difficult to lose weight. So you have to be even more consistent and careful. Some of these drugs include antidepressants, birth control pills, and steroids.”

Other possible side effects from medicine include a stimulated appetite, a decrease in metabolism, increased storage of body fat, and impaired tolerance to exercise.

According to Valdez, classes of medications with possible weight change side effects include antihypertensives (e.g., beta blockers such as metoprolol and calcium channel blockers), diabetes medications (e.g., insulin and sulfonylureas such as glyburide, glipizide, and thiazolidinediones), steroids (e.g., prednisone, chemotherapy drugs, and contraceptive pills), antidepressants (MAOIs such as trazodone and SSRIs such as Zoloft and Remeron), antipsychotics for mental illness, and anticonvulsants for neurological conditions such as epilepsy (e.g., gabapentin and pregabalin).

Conversely, certain medications can suppress your appetite, causing unintentional weight loss. This includes medications for cancer, HIV, and dementia, Valdez notes. If you experience any of these symptoms, bring it up with your doctor.

Medical Conditions

Like medications, certain conditions and illnesses, ranging from the common cold to serious diseases, can have an impact on your weight.

“When we are sick or healing, our body tends to go into a catabolic state where it is using more energy than usual. This is because it is trying to repair or heal itself,” Shapiro explains. “During these times, it is important to fuel correctly and stay hydrated. Your energy needs to increase, even if you aren’t moving around much and don’t feel like eating.”

It’s paramount to maintain a healthy diet and eat enough during periods of sickness so that your body is able to heal. You may find that you need to eat even more than usual because it takes a lot of internal energy to recover.

Another way to recover is through yoga and meditation. We have the top trainers walking you through each audio program in the app.

“Other times, illnesses such as thyroid issues can cause weight gain, as your thyroid can be underactive. Your thyroid controls your metabolism. So you may put on weight even if your diet and lifestyle have not changed,” Shapiro continues.

“Diabetes or insulin resistance (such as PCOS) can also cause weight gain. Your cells do not use sugar as energy. They store it as fat. Even if you are eating healthy carbohydrates like fruit and grains, your body will not use them for energy. You may put on weight.” If you believe that you have any of these conditions, consult your doctor.

There are a number of factors that affect weight gain and weight loss. If you’re struggling to lose or gain weight while maintaining a balanced diet and exercise routine, talk to your doctor. He or she will be able to provide solutions individual to your situation.

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