nexplained weight gain can be an incredibly frustrating experience to go through, especially if you’ve been making a point to be active and eat healthy. But there are some things you could be doing—or conditions you may unknowingly have—that could put you at an elevated risk of sudden or unexpected weight gain.
The good news is that once you identify these triggers, many of them can be reversed. Things like getting a handle on stress, logging more hours of sleep, and putting down the salt shaker can go a long way in helping you ward off unwanted pounds. Here are 15 causes of unexplained weight gain and what to do about them.
When you’re in a constant or daily state of stress, your cortisol levels increase. And research shows that excess cortisol can lead to weight gain, especially in the face and abdomen. This, says Dr. Josh Axe, a clinical nutritionist and founder of Ancient Nutrition, is because the stress hormone turns on fat storage in the body.
“Increased cortisol can also cause weakness, widespread inflammation and pain, which can lead to a more sedentary lifestyle and weight gain,” he explains. To relieve stress, Axe suggests taking frequent walks outdoors, practicing yoga, journaling and using relaxing essential oils like lavender and bergamot. “It may also help to reach out for support, either from a trained therapist or loved one,” he explains.
Not getting a proper night’s sleep can cause people to turn to food as a means of making up for lost energy, thus leading to the potential of packing on some extra pounds.
“This is because lack of sleep may disrupt appetite hormones that regulate hunger,” says Alli Gregg, a clinical dietitian with Mayo Clinic. “Ghrelin, a hunger hormone, rises, and leptin, a satisfaction hormone, falls. This leads to eating a greater number of calories and feeling less satisfied after eating,” she adds. “Try to get at least seven hours of sleep a night to reduce your risk of sleep-related weight gain.”
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Many people use mealtime as an opportunity to multi-task. “And while you’re scrolling on your phone, watching television, working on your laptop or driving, you are likely over-eating without even noticing it,” says Gregg. Studies have found this to be the case, with a collection of research published in the American Journal of Clinical Nutrition concluding that distracted eating increased the chances of over-eating. This, says Gregg, can definitely lead to weight gain. She suggests trying to limit or avoid screen time while eating. “Place your phone out of reaching distance, turn the television off, and do not eat in front of your computer,” Gregg explains. “This will allow you to slow down and enjoy your meal and will allow you to be much more aware of what and how much you are eating.”
Cramming too much into your smoothie
“Regularly drinking smoothies is an easy way to see unexpected weight on the scale,” says Gregg. She adds that there’s a misconception that smoothies are health drinks. “It is true that they often are made with fruits and vegetables, which are extremely healthy. However, there also are a lot of additives blended in, especially when enjoying from a restaurant or pre-bottled item.” Smoothies and juices can be extremely high in calories and sugar. For example, Gregg cites that the “Daily Warrior” from Smoothie King contains 680 calories and 58 grams of sugar. “That exceeds the calorie recommendation for an entire meal for a lot of people,” she explains.
When choosing a smoothie, Gregg says to forgo the added sugar. “Ask for water or a milk product such as almond milk to be used as the base instead of juice,” she suggests. Also, ask for no sugar or sugar substitutes to be added. And Gregg says to “skip the options that exceed 500 calories unless using as a meal replacement.”
Not changing up your workout
“You may be experiencing unexpected weight gain because you are doing the wrong workout,” explains Saara Haapanen, a personal trainer and performance consultant in Colorado. She notes that if you’re working out and you’ve plateaued or are gaining weight, you should probably change up your routine, especially if you’re doing the same thing all the time. “As humans, we adapt and need to be consistently challenged. The same goes for workouts,” says Haapanen. She illustrates this with the following example:
“If you do a lot of steady-state cardio (i.e. running on the treadmill at the same speed) you will become more efficient at it. Running will become easier and you will get a lot of cardiovascular benefits but once you get to a point, it won’t be a good use of your time to change your body.”
In order to mitigate this, Haapanen says you need to change things up. “You can still run but change it up. Do 1 min of sprinting, add in hills, and vary your speed.” She says it’s all about keeping your body guessing. If you’re doing the same workout every day change it up, add in a strength-training workout, a HIIT, Pilates, yoga, dance, or something else you enjoy. “If it doesn’t challenge you, it doesn’t change you.”
If you’re putting on a few pounds and feeling off, it might be time to take a home pregnancy test. Pregnancy, says Dr. David Cutler, a family medicine physician at Providence Saint John’s Health Center in Santa Monica, California, can be a definite cause of weight gain. And if you suspect that you’re pregnant, it’s a good time to call your doctor. One study that analyzed the rate of weight gain in 3,800 women found that healthy women eating without restrictions put on an average of 2.2 pounds in the first trimester. And the American Pregnancy Association says the average weight gain for females is 1-4.5 pounds in the first trimester and 1-2 pounds a week in the second and third trimesters.
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Retaining fluids can set you up to pack on a bit of water weight. “This can be due to a high sodium intake, which can cause fluid retention, especially for those with kidney disease, heart failure, liver disease,” says Melanie Steele, a registered dietitian in Vancouver.
She says that keeping your sodium intake to the recommended 2,300 mg per day for the general population can help prevent excess fluid retention. And those with kidney disease, heart failure, or liver disease may need to follow a lower sodium diet based on recommendations from their doctor or dietitian to keep fluid retention at bay. “In some cases, diuretics are required to remove excess fluid or keep the body from retaining it,” adds Steele. “A large weight gain in a short period of time is reason to call your doctor.”
Having an underactive thyroid may cause you to put on some unexpected weight. Steele explains that this scenario occurs when your thyroid doesn’t produce enough hormones. “The hormones released by the thyroid help regulate your body’s energy use,” she says. According to Steele, a synthetic thyroid hormone is typically the treatment, and once diagnosed and on proper replacement therapy, people are likely to see their weight stabilize. If you suspect you have this condition, definitely go see your doctor.
Drugs and certain medications
You may be on a variety of medications ordered by your physician, however, some of these may come with the side effect of unwanted extra pounds. According to a 2018 study, “antipsychotics, antidepressants, antihyperglycemics, antihypertensives and corticosteroids all contain medications that were associated with significant weight gain.”
Your birth control may be another culprit—ever wonder why some women gain weight on birth control and not others? One study revealed that your individual genes might play a role in determining whether or not your birth control leads to a few extra pounds.
Your menstrual cycle
You may feel bloated before or during your menstrual cycle but have you ever stepped on the scale during that time? Your weight may be up due to your fluctuating hormones. This is something that Herrington’s clients complain about all the time. Her suggestion for combatting it? Water. “While it may seem counterintuitive, drinking more water can help combat the extra pounds you experience during your period,” she says. “Better hydration helps flush out your system.”
“If you are dehydrated, your digestion and the rate at which your body processes food into energy decreases leading to potential fatigue and weight gain,” explains Lisa Herrington, a personal trainer and founder of FIIT House in Davis, California. She notes that dehydration also contributes to slower metabolic processes, which may hinder your body’s ability to burn calories at a higher rate.
To increase water intake, Herrington says to begin each morning with 1-2 cups of water. “Carry a bottle of water around as a reminder to sip throughout the day aiming for at least 8 (women), 12 (men) cups of water per day, more if you live in a warm climate and/or exercise regularly.” Other ways to get in enough water, per Herrington, include sipping on herbal tea, water infused with fruit, mint or cucumbers, as well as fueling your body with foods such as fruit and vegetables that have a higher water content.
Polycystic Ovarian Syndrome
Polycystic Ovarian Syndrome (PCOS) can also cause you to gain weight without necessarily increasing your food intake or eating unhealthily, says Dr. Ava Williams, a primary care doctor at Doctor Spring. “Women with PCOS may develop insulin resistance and decrease the body’s ability to sugar in the body into energy,” she explains. If you are experiencing these symptoms, speak to your gynecologist or general practitioner to discuss different treatment options.
Related: What is PCOS? We Break Down All the Myths Around Polycystic Ovary Syndrome
“Smoking, although dangerous for health, does provide a slight metabolism boost from the stimulants in nicotine,” explains Erin Palinski-Wade, a registered dietitian and diabetes expert in New York City. She says that when you quit smoking, your metabolism can slow slightly as your body adjusts to the lack of nicotine. However, this slight metabolism shift isn’t the sole reason for weight gain. “Many individuals seek the ‘hand to mouth’ habit that smoking provided and find themselves mindlessly snacking more as a replacement to smoking, which can lead to significant weight gain,” Palinski-Wade adds.
In some rare cases, a condition known as Cushing’s Syndrome can also lead to unwanted pounds. “Cushing’s occurs due to prolonged exposure of high levels of the stress hormone cortisol,” says Palinski-Wade. She explains that when this stress hormone is elevated, it causes the body to store fat versus burn it, resulting in increased fat storage, specifically in the abdominal area. “Since an accumulation of visceral fat can increase insulin resistance, this can exasperate weight gain.”