What nutrient causes the most weight gain?
Quickly Gaining Weight? These 8 Common Reasons Might Be Why
If you’re quickly gaining weight, there are many possible reasons.
Samantha Lauriello is a social media strategist and editor. She was previously an assistant editor at Health before moving over to Travel + Leisure as a social media editor.
Updated on August 26, 2022
Medically reviewed by
Jonathan Purtell, MS, RDN, CDN, is a registered dietitian at Lenox Hill Hospital. His primary interests include surgical and neurosurgical intensive care, orthopedic, obese/post-bariatric, and gastrointestinal patients.
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If you haven’t changed your eating and exercise habits and are still gaining weight, something more could be going on.
Carrying extra pounds isn’t necessarily a problem, of course. But it could signal an underlying medical issue you’ll want to address. Maybe it’s a hormone condition, a mood disorder, or another factor altering your physiology without you realizing it. The only way to be entirely sure of what it means is to consult your healthcare provider. In the meantime, consider these eight health-related reasons that might explain why the number on the scale has soared.
Underactive Thyroid (Hypothyroidism)
Aside from realizing that your jeans are snugger, have you noticed other body changes—like exhaustion, drier skin, or thinner hair? These are all signs of hypothyroidism, a condition in which the butterfly-shaped thyroid gland in your neck isn’t producing enough thyroid hormones. Your thyroid is a master gland controlling many body functions, so when it’s not working right, symptoms appear throughout your body, according to the American Thyroid Association.
A major function the thyroid controls is metabolism. «Think of your body as a car. You have an engine, and the thyroid hormone maintains the idling of the engine,» Michael Nusbaum, MD, a surgeon and founder of Nusbaum Medical Centers, told Health. «If you’re not producing enough thyroid hormone, your idle gets turned down, and you’re not burning as much energy overall.» When your resting metabolism slows, it decreases the number of calories you burn throughout the day, according to Harvard Health Publishing.
One in eight women will develop a thyroid disorder during her lifetime, according to the American Thyroid Association. Dr. Nusbaum said other symptoms to look out for are muscle weakness, constantly feeling cold, bloating, and constipation. If your doctor diagnoses hypothyroidism, you’ll likely be prescribed an oral replacement for thyroid hormone that can alleviate symptoms within weeks.
Polycystic Ovary Syndrome (PCOS)
Polycystic ovary syndrome (PCOS) is another condition caused by out-of-whack hormones. This endocrine disorder is characterized by an imbalance in the sex hormones estrogen and testosterone (women produce testosterone, too, though in much smaller quantities than men do). This imbalance leads to irregular periods, acne, and even facial hair growth, according to the US Department of Health & Human Services Office on Women’s Health.
This disorder, which affects one in 10 women of childbearing age, also disrupts the way the body uses insulin—the hormone responsible for converting carbohydrates into energy, said Dr. Nusbaum. Yep, you guessed it, that means weight gain. When your body becomes insulin resistant, the sugars and starches you consume are stored as fat instead of turned into fuel, explained Dr. Nusbaum.
While there’s no cure for PCOS, people who have it can manage their symptoms with lifestyle changes and medication. Your healthcare provider will help you find the right method for you.
Weight From Depression and Anxiety
Dealing with anxious or sad feelings by mindlessly munching is something almost all occasionally do. But either of these mood disorders can make overeating a common coping mechanism, according to a 2019 study in the International Journal of Behavioral Nutrition and Physical Activity. Dr. Nusbaum gave the example of breaking open a bag of chips. After three, four, then five handfuls, «you’re not even tasting the chips anymore, your taste buds are completely saturated with the flavor, but you’re still eating, and you’re thinking, Why am I still eating?«.
Depression and anxiety can both bring on fatigue, irritability, and a lack of focus. All three can throw you off your game when you work out or lead you to ditch the gym altogether.
Reflect on your mood over the past few weeks. If you’ve been consistently down on yourself, on edge, disinterested in things you usually enjoy, or have had trouble sleeping, consider asking your healthcare provider for a referral to a mental health professional. A mental health professional can help get to the bottom of what’s happening. And proper treatment can help you maintain a healthy weight.
Perimenopause and Menopause Weight Gain
A drop in estrogen levels during menopause and perimenopause (the years leading up to menopause) can cause weight gain, according to a 2017 review in Mayo Clinic Proceedings. «The rapid reduction in the amount of hormones present in your body throws you off-kilter pretty quickly,» said Dr. Nusbaum.
In addition, the extra weight associated with menopause tends to accumulate in the abdominal area, specifically increasing the risk of cardiovascular disease and high blood pressure, according to the same review. Eating a healthy diet and exercising regularly can help avoid gaining weight.
Cortisol, nicknamed the stress hormone, is what your body releases in response to overwhelming or dangerous situations, Diondra Atoyebi, DO, a family physician at Piedmont Healthcare in Georgia, told Health. But when your system makes too much cortisol over an extended period, you can develop Cushing’s disease. One unpleasant side effect: Abnormal fatty deposits in the abdominal area and around the face.
If you’re taking long-term steroids, you’re more likely to develop Cushing’s disease, said Dr. Atoyebi. The condition can also be brought on by tumors on the pituitary gland in the brain, which triggers an uptick in the production and release of adrenocorticotropic hormone—the catalyst that signals the adrenal glands to produce cortisol, according to Oregon Health & Sciences University (OHSU) Brain Institute.
Weight gain, especially in the upper body, is a hallmark sign of Cushing’s; other symptoms include stretch marks, acne, and easy bruising, according to OHSU Brain Institute. Depending on the cause, Cushing’s disease can be treated in various ways. If you have Cushing’s disease, your healthcare provider will help you determine what treatment best suits you.
Ovarian or Uterine Tumor
In September 2018, Case Reports published a case of a 53-year-old woman in Singapore who had a 61-pound tumor removed from her uterus after showing up at the hospital struggling to breathe. To grow so large, the tumor was likely developing inside her for years. It’s an extreme case, but it shows that if left untreated, large pelvic area tumors, such as uterine or ovarian tumors, can distend the abdomen the way excess fat does and send the scale soaring. In the case of the Singaporean woman, the tumor was benign, but others can be cancerous.
In addition to weight gain, symptoms of ovarian or uterine tumors include lower back pain, vaginal bleeding, painful intercourse, and constipation, according to the American Cancer Society. But these signs are common for other conditions as well, said Dr. Nusbaum, which is why you should always consult your healthcare provider to confirm the root cause of the problem.
Before starting any new over-the-counter (OTC) or prescription medication, ask your healthcare provider if gaining weight is a possible side effect. Psychiatric medications, especially for depression and bipolar disorder, commonly cause weight gain, said Dr. Nusbaum. «They act centrally on the brain, and while they intend to lower your depression, they inadvertently increase your desire to eat.»
Meds that combat high blood pressure can also cause weight gain, Susan Besser, MD, a family practitioner at Mercy Personal Physicians in Maryland, told Health. Another culprit is taking insulin for diabetes, as insulin therapy can sometimes cause weight gain. According to the American Diabetes Association, staying active and eating a balanced diet can help you manage the disease without adding excess weight.
Insomnia and Your Weight
If you try to work all day on only four hours of sleep, you’ll probably turn to snacking on simple carbs—chips, cookies, candy—to give you quick energy boosts to get through the day. Why does exhaustion trigger cravings like these? Dr. Besser said lack of sleep messes with your hunger-regulating hormones. Levels of ghrelin, a hormone that tells your body it’s time to eat, increase after a restless night, according to a 2015 study in Obesity. At the same time, leptin, the hormone that signals fullness, may plunge. Put the two together, and no wonder your belt feels tight. This doesn’t just happen overnight, though. It’s persistent insomnia that causes weight gain.
Sleep deprivation can also affect your decision-making. For example, let’s say you can eat either a banana or a cookie. When you’re tired, you become more impulsive, and that impulsivity can coax you into grabbing higher-calorie snacks, according to a 2016 study in the journal Sleep. Sugar is also instant energy, something your body will crave when you’re exhausted. A 2018 study published in the American Journal of Clinical Nutrition found that getting more shuteye can mean consuming up to 10 fewer grams of sugar throughout the day.
And while having a cookie isn’t going to immediately make you gain weight, when your habit is to choose sugary foods over more nutrient-dense options, you may find that weight creeping up.
There are many possible causes of rapid weight gain. From medical conditions to sleep deprivation (which can cause medical conditions), some of the reasons are out of your control. You do, however, have control over what you do about them. See your healthcare provider, who can help you figure out the cause of your sudden weight gain. Once the cause is determined, you’ll find out what you can do to get back to a healthy weight.
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Weight gain is an increase in body weight. This can involve an increase in muscle mass, fat deposits, excess fluids such as water or other factors. Weight gain can be a symptom of a serious medical condition.
Description [ edit ]
Weight gain occurs when more energy (as calories from food and beverage consumption) is gained than the energy expended by life activities, including normal physiological processes and physical exercise. 
If enough weight is gained due to increased body fat deposits, one may become overweight or obese, generally defined as having more body fat (adipose tissue) than is considered good for health.  The Body Mass Index (BMI) measures body weight in proportion to height, and defines optimal, insufficient, and excessive weight based on the ratio. 
Having excess adipose tissue (fat) is a common condition, especially where food supplies are plentiful and lifestyles are sedentary.  Overweight and obesity may increase the risk of several diseases, such as diabetes, heart disease, and some cancers, and may lead to short- and long-term health problems during pregnancy.  Rates of obesity worldwide tripled from 1975 to 2016 to involve some 1.8 billion people and 39% of the world adult population. 
A commonly asserted «rule» (the Wishnofsky Rule, aka Wishnofsky’s Rule) for weight gain or loss, is based on the research of Max Wishnofsky (December 17, 1899 – August 2, 1965), a Russian-born physician who had a medical practice in Brooklyn, New York. The Wishnofsky Rule states that one pound of human fat tissue contains about 3,500 kilocalories (often simply called calories in the field of nutrition). Wishnofsky conducted a review of previous observations and experiments on weight loss and weight gain, and stated his conclusions in a paper he published in 1958.  Thus, according to the Wishnofsky Rule, eating 500 fewer calories than one needs per day should result in a loss of about a pound per week. Similarly, for every 3500 calories consumed above the amount one needs, a pound will be gained.  
Wishnofsky noted that previous research suggested that a pound of human adipose tissue is 87% fat, which equals 395 grams of fat. He further assumed that animal fat contains 9.5 calories per gram. Thus one pound of human fat tissue should contain 3750 calories. He then critically analyzed the relevant literature and applied a number of additional assumptions, including that the diet contains sufficient protein and that the person is in glycogen and nitrogen (protein) equilibrium, leading to most weight loss stemming from the catabolism of fat. He concluded that a 3500 calorie excess or deficit for a person meeting his assumptions, would lead to the gain or loss, respectively, of one pound of body weight. He noted that if the assumptions he made are not met, a deficit of 3500 calories would not necessarily equate to a pound of weight loss. [ citation needed ]
Wishnofsky did not take into account numerous aspects of human physiology and biochemistry which were unknown at the time. The claim has achieved the status of a rule of thumb and is repeated in numerous sources, used for diet planning by dietitians and misapplied at the population level as well.  
Causes [ edit ]
In regard to adipose tissue increases, a person generally gains weight by increasing food consumption, becoming physically inactive, or both. When energy intake exceeds energy expenditure (when the body is in positive energy balance), the body can store the excess energy as fat. However, the physiology of weight gain and loss is complex involving numerous hormones, body systems and environmental factors. Other factors besides energy balance that may contribute to gaining weight include:
Social factors [ edit ]
A study, involving more than 12,000 people tracked over 32 years, found that social networks play a surprisingly powerful role in determining an individual’s chances of gaining weight, transmitting an increased risk of becoming obese from wives to husbands, from brothers to brothers and from friends to friends.  
The human microbiota facilitates fermentation of indigestible carbohydrates to short-chain fatty acids, SCFAs, contributing to weight gain.  A change in the proportion of Bacteroidetes and Firmicutes may determine host’s risk of obesity. 
Sleep and stress [ edit ]
Lack of sufficient sleep has been suggested as a cause for weight gain or the difficulty in maintaining a healthy weight.  Two hormones responsible for regulating hunger and metabolism are leptin, which inhibits appetite and increases energy expenditure, and ghrelin, which increases appetite and reduces energy expenditure.  Studies have shown that chronic sleep deprivation is associated with reduced levels of leptin and elevated levels of ghrelin, which together result in increased appetite, especially for high fat and high carbohydrate foods.  As a result, sleep deprivation over time may contribute to increased caloric intake and decreased self-control over food cravings, leading to weight gain.
Hormone and neurotransmitter imbalances [ edit ]
Weight gain is a common side-effect of certain psychiatric medications. 
Pathologies [ edit ]
Effects [ edit ]
Excess adipose tissue can lead to medical problems; however, a round or large figure does not necessarily imply a medical problem, and is sometimes not primarily caused by adipose tissue. If too much weight is gained, serious health side-effects may follow. A large number of medical conditions have been associated with obesity. Health consequences are categorised as being the result of either increased fat mass (osteoarthritis, obstructive sleep apnea, social stigma) or increased number of fat cells (diabetes, some forms of cancer, cardiovascular disease, non-alcoholic fatty liver disease).   There are alterations in the body’s response to insulin (insulin resistance), a proinflammatory state and an increased tendency to thrombosis (prothrombotic state). 
See also [ edit ]
- Healthy diet
- Fad diet
- Fat feminism
- Fat acceptance movement
- Weight loss
References [ edit ]
- ^ ab«Aim for a healthy weight». National Heart, Lung, and Blood Institute, US National Institutes of Health. 2020 . Retrieved 24 January 2020 .
- ^ abc
- «Health risks of being overweight». National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health. 2020 . Retrieved 24 January 2020 .
- «Obesity and overweight». World Health Organization. 16 February 2018 . Retrieved 24 January 2020 .
- Wishnofsky, M (1958). «Caloric equivalents of gained or lost weight». Am J Clin Nutr. 6 (5): 542–546. doi:10.1093/ajcn/6.5.542. PMID13594881.
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- Hall, Kevin; Chow, CC (June 18, 2013). «Why is the 3500 kcal per pound weight loss rule wrong?». International Journal of Obesity. 37 (12): 1614. doi:10.1038/ijo.2013.112. PMC3859816 . PMID23774459.
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- Stein, Rob (2007-07-26). «Obesity Spreads In Social Circles As Trends Do, Study Indicates». Washington Post. p. A01.
- Nicholas A. Christakis, M.D., M.P.H., and James H. Fowler (2007-07-26). «The Spread of Obesity in a Large Social Network over 32 Years». NEJM. 357 (4): 370–379. CiteSeerX10.1.1.581.4893 . doi:10.1056/NEJMsa066082. PMID17652652. > : CS1 maint: multiple names: authors list (link)
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- Arora, Tulika; Sharma, Rajkumar (2011). «Fermentation Potential Of The Gut Microbiome: Implications For Energy Homeostasis And Weight Management». Nutrition Reviews. 69 (2): 99–106. doi:10.1111/j.1753-4887.2010.00365.x. PMID21294743.
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- Vorona, Robert D.; Winn, Maria P.; Babineau, Teresa W.; Eng, Benjamin P.; Feldman, Howard R.; Ware, J. Catesby (2005-01-10). «Overweight and Obese Patients in a Primary Care Population Report Less Sleep Than Patients With a Normal Body Mass Index». Archives of Internal Medicine. 165 (1): 25–30. doi: 10.1001/archinte.165.1.25 . ISSN0003-9926. PMID15642870.
- Patel, Sanjay R.; Hu, Frank B. (January 17, 2008). «Short sleep duration and weight gain: a systematic review». Obesity (Silver Spring). 16 (3): 643–653. doi:10.1038/oby.2007.118. PMC2723045 . PMID18239586.
- Newcomer JW (2005). «Second-generation (atypical) antipsychotics and metabolic effects: a comprehensive literature review». CNS Drugs. 19 Suppl 1: 1–93. doi:10.2165/00023210-200519001-00001. PMID15998156. S2CID36435377.
- Haslam D, James WP (2005). «Obesity». The Lancet. 366 (9492): 1197–1209. doi:10.1016/S0140-6736(05)67483-1. PMID16198769. S2CID208791491.
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15 Best and Worst Foods for Weight Loss
Put down those potato chips and pick up some pistachios! New research reveals the most common foods that cause weight gain, and the healthier choices that actually help you lose weight.
The average adult gains one pound per year, and this steady weight creep may be directly related to what (and not just how much) you eat, according to a new study published in the New England Journal of Medicine. Researchers analyzed data collected over 20 years from more than 120,000 U.S. men and women who were not obese and were free of chronic diseases, and identified a number of specific foods linked to weight gain — or weight loss. Eating just one additional daily serving of French fries led to a 3.35-pound weight gain over a four-year period, the study found, while adding yogurt to your diet was linked to a 0.82-pound loss over the same timeframe.
The findings further fuel the theory that little diet tweaks can have a big impact on your weight — the average participant gained 16 pounds during the course of the study — and overall health. «This suggests that the path to eating fewer calories is not simply to count calories, but to focus on consuming a more healthy diet in general,» the study’s lead author, Dariush Mozaffarian, MD, associate professor in the department of epidemiology at the Harvard School of Public Health, told The Wall Street Journal.
Also important: Rounding out a healthy diet with smart lifestyle choices. The study found that weight gain also occurred among those who slept less than 6 or more than 8 hours, who watched the most TV, and who drank the most alcohol.
So are your daily favorite foods padding or slimming your waistline? Click through to find out how much weight they caused people to gain or lose over a four-year period.
Participants lost 0.49 pounds over a four-year period by adding fruit to their daily diet. The new USDA MyPlate recommends eating fruits and veggies at every meal.
Food Fact: 1 cup of berries = 83 calories
Adding more veggies, with their high fiber and water content, can help you fill up and slim down. According to this major diet study, eating vegetables every day led to a loss of 0.22 pounds.
Food Fact: 1 cup of red or bell peppers = 46 calories
Nuts may be high in fat, but it’s the slimming monounsaturated kind that experts say we need to eat more. And not surprisingly, they were among the foods that helped prevent weight gain. Participants who ate these nutrient- and fiber-rich treats lost 0.57 pounds.
Food Fact: ½ cup of almonds = 265 calories
Whole-Fat Dairy Foods
Got milk? You’re better off sticking with skim or low-fat dairy. Participants who ate whole-fat dairy (butter, cheese, and whole-fat milk) gained 0.10 pounds.
Food Fact: 8 fluid ounces of regular milk = 149 calories; the same amount of skim milk has 83 calories
Low-Fat Dairy Foods
Yogurt may be the ultimate slimming food. Those who ate it regularly lost an average of 0.82 pounds.
Food Fact: 5 oz. plain Greek yogurt = 80 calories