9 Causes of Fat Gain (Not One Being Food ...)
© 2026 Health Realizations, Inc.
Have you heard people say they just can't lose weight even when they nearly starve themselves? Ever felt that way yourself? Or concerns about weight loss drugs (GLP-1)?
A large number of Americans struggle to lose weight every day, despite adhering to healthy diets and regular exercise programs. So what is really going on? While diet and exercise are certainly the two biggest factors, and eating healthy and exercising will result in weight loss for the majority of people who try them, for some it’s just not enough.
In fact, there are several causes of weight gain that have nothing to do with diet or even exercise … so if you’ve been stuck in a weight-loss plateau, keep reading to find out if one of these explanations may be to blame …
1. Lack of Sleep
Too little sleep can have a big impact on your waistline, and not in a good way. How? By altering levels of hormones that regulate hunger. According to one study by University of Chicago researchers, people who slept only four hours a night for two nights had an 18 percent decrease in leptin, a hormone that signals your brain you’ve had enough food, and a 28 percent increase in ghrelin, the “hunger” hormone.
Not surprisingly, after getting such little sleep, the participants noted a 24 percent increase in appetite, with a particular desire for sugary, salty and starchy foods, like candy, chips and pasta.
A separate study also found that people who sleep less than four hours a night are 73 percent more likely to be obese than people who sleep more, while a new study in the International Journal of Obesity found that middle-aged women who have trouble sleeping may gain more weight than well-rested women.
In short, once your sleep patterns have been disrupted, your body will be prone to weight gain and overeating. Meanwhile, overeating may further throw off your circadian rhythm, or sleep-wake cycle, leading to a vicious cycle that can be hard to overcome.
GLP-1 medications (like Ozempic, Wegovy, or Mounjaro) do not directly impact sleep chemistry, but GLP-1 side effects can cause insomnia, like nighttime nausea, slowed digestion, or blood sugar fluctuations vivid dreams, or a "wired" feeling. Thankfully, these issues are usually temporary and felt to be manageable.
Creating a relaxing bedtime routine, which can include a warm bath, a foot massage, stretching, or listening to the wonderful soothing music, can help you to fall asleep and stay asleep.
2. Sitting Too Much -- “Sittosis”
Americans spend an excess of time sitting -- leading to a variety of “sittosis” conditions, not the least of which is weight gain. Even independent of how much time you spend exercising, if you spend the bulk of your day sitting you could be inadvertently packing on the pounds.
Part of the problem is sitting stops the circulation of lipase, an enzyme that absorbs fats. So instead of being absorbed by your muscles, when you’re sitting fat recirculates in your bloodstream where it may end up stored as body fat, clogging arteries or contributing to disease and weight gain.
A recent study even found sitting time was a predictor of weight gain in Australian women, even after adjustments were made for diet and exercise.
According to Marc Hamilton, Ph.D., a professor of biomedical sciences at the University of Missouri in Columbia, numerous studies show rates of heart disease, diabetes and obesity are doubled and even tripled in people who sit a lot.
For instance, a Canadian study showed that screen time is linked to obesity in adults. After surveying 42,600 men and women, researchers found:
-
Those who watched more than 21 hours of TV a week were 80 percent more likely to be obese than those who watched 5 hours or less.
-
Men who spent a lot of leisure time in front of a computer were 20 percent more likely to be obese, and women 30 percent more, than those who did not.
Research by Hamilton and others found sitting not only has a negative effect on fat and cholesterol metabolism, but also stimulates disease-promoting processes. What’s more, exercising, even for an hour a day, does not reverse this effect.
"The enzymes in blood vessels of muscles responsible for 'fat burning' are shut off within hours of not standing," Hamilton told ScienceDaily.com. "Standing and moving lightly will re-engage the enzymes, but since people are awake 16 hours a day, it stands to reason that when people sit much of that time they are losing the opportunity for optimal metabolism throughout the day."
So take the opportunity to stand rather than sit as often as you can. Stand while watching your kids play at the park, stand while you talk on the phone or watch TV, and any other time you can “get up off your butt” … do!
One simple tip is every morning when you first awake make a routine of stretching for 10 to 15 minutes.
Then, every evening set a time for a 30-minute focused exercise routine. This doesn’t have to require an expensive health club membership.
According to Stanford University “...unwanted side effect of GLP-1 drugs: losing muscle strength along with fat. Millions of Americans are currently taking GLP-1 medications such as Ozempic or Wegovy for weight loss. But along with the fat, many are quietly losing something else: muscle. Unlike fat, muscle doesn’t return quickly, and muscle loss can have deleterious effects on strength, mobility and overall health.”
3. Intrauterine and Childhood Programming
GLP-1 medications are contraindicated during pregnancy due to potential risks observed in animal studies, and doctors recommend stopping them 1 to 3 months before conception.
Although the link is still being established, some studies have found a link between a mother’s weight during pregnancy and the future weight of her unborn child.
According to one study in Current Opinion in Obstetrics and Gynecology:
“Maternal obesity … increases the risk of delivering a large for gestational age or macrosomic neonate, who is in turn at an increased risk of subsequent childhood obesity and its associated morbidity.”
On the other hand, studies have also shown that you may be prone to obesity as an adult if your mother was undernourished during pregnancy. An animal study found that this may impact lifestyle choices later on, with rat offspring of undernourished rats more likely to be sedentary in later life. The researchers wrote:
“We have shown that predispositions to obesity, altered eating behavior, and sedentary activity are linked and occur independently of postnatal hypercaloric nutrition.
Moreover, the prenatal influence may be permanent as offspring of undernourished mothers were still significantly less active compared with normal offspring at an advanced adult age, even in the presence of a healthy diet throughout postnatal life.”
There is also the issue of childhood nutrition and weight. If a child is obese between the ages of 10 and 13, they have an 80 percent chance of being obese as an adult, according to the American Academy of Child & Adolescent Psychiatry.
GLP-1 drugs while FDA-approved only for teens 12 and older, the risks include stunted development from inadequate nutrition, unknown long-term brain and bone effects, and gastrointestinal distress. Off-label use in younger children carries even higher, unstudied dangers.
4. Depression
Depression and obesity have a reciprocal relationship in that people who are depressed are more likely to become obese, while those who are obese are more likely to become depressed. Among initially normal-weight individuals, depression increases the risk of obesity by 58 percent, according to a new study by Dutch researchers.
For starters, it’s common for people with depression to overeat -- particularly foods high in sugar and fat, i.e. “comfort foods” -- as well as reduce their physical activity levels.
"Activation of the endocannabinoid system, which increases appetite and may simultaneously alleviate depression, is likely to reinforce this eating behavior. Socioeconomic disadvantage may further exacerbate the over-consumption of comfort foods because of their low cost," Dr. Evan Atlantis from the University of Adelaide's School of Medicine told Medical News Today.
If you’re currently depressed, you should seek help from a knowledgeable natural health care practitioner. You can also try adding regular exercise to your routine, as it’s effective at both relieving depressive symptoms and helping to maintain a healthy weight.
“A new era of weight loss: Mental health effects of GLP-1” ... according to the American Psychological Association “GLP-1s might drive depression... almost double the risk of major depression.”
Ideally, try to avoid taking antidepressants, as they’re actually associated with obesity (see below).
5. Certain Medications
Certain prescription drugs cause weight gain as a side effect. According to Consumer Reports, these include:
-
Epilepsy drugs: Depakote, Carbatrol, Epitol, Tegretol and Tegretol-XR for epilepsy are known to cause weight gain.
Other drugs, including contraceptives (the birth control pill), diabetes drugs and blood pressure drugs, are also known to cause weight gain. Considering that the use of prescription drugs in general is rising rapidly, this is a serious consideration in the battle of the bulge.
The average American aged 19-64 takes over 11 prescriptions per year!
Weight loss drug medications (like Ozempic, Wegovy, Mounjaro, and Zepbound) can interact with certain other drugs. Primarily issues are that they delay stomach emptying (gastroparesis) and affect how your body metabolizes medication.
High-Risk Drug Categories
-
Oral Medications with a Narrow Therapeutic Index: Because GLP-1s slow digestion, oral drugs may take longer to absorb or might not be absorbed as effectively. This can impact the effectiveness of critical medications like digoxin (for heart conditions), warfarin (blood thinners), and levothyroxine (thyroid medication).
-
Birth Control Pills: The delayed absorption can interfere with the way oral contraceptives are taken up by your body, potentially making them less effective.
-
Blood Pressure and Mood Medications: Combining GLP-1s with antihypertensives, ADHD medications, or mood disorder drugs can sometimes cause adverse reactions, altered blood pressure, or increased hospital visits for dehydration.
-
Insulin and Sulfonylureas: Taking GLP-1s alongside diabetes drugs that lower blood sugar significantly increases your risk of developing hypoglycemia (dangerously low blood sugar).
Key Health Risks
When combining medications or taking GLP-1s generally, be aware of these potential complications:
-
Gastrointestinal Issues: Severe nausea, vomiting, or diarrhea can cause dangerous dehydration.
-
Serious Rare Side Effects: GLP-1s are linked to rare but serious risks such as pancreatitis (inflamed pancreas), gallbladder disease, and kidney injury.
-
Who Should Avoid Them: Individuals with a personal or family history of medullary thyroid cancer, multiple endocrine neoplasia syndrome type 2 (MEN 2), or a history of severe gastrointestinal disease (like gastroparesis) should generally not take these medications.
For in-depth guidance on how GLP-1s interact with your specific prescriptions, check out resources like GoodRx or consult the Endocrinology Advisor guide on metabolism risks.
When would you need to take a GLP-1 agonist?
Healthcare providers prescribe GLP-1 agonists for two conditions: Type 2 diabetes and obesity.
Per the Cleveland Clinic:
GLP-1 agonists are a class of medications by design were to help manage blood sugar (glucose) levels in people with Type 2 diabetes. Some GLP-1 agonists can also help treat obesity.
GLP-1 agonists alone can’t treat Type 2 diabetes or obesity. Both conditions require other treatment strategies, like lifestyle and dietary changes.
Today many people NOT over weight are using these for aesthetic reasons to feel good about their appearance over that of possible health concerns.
To Calculate Your BMI:
You can calculate BMI yourself with these steps:
-
Multiply your weight in pounds by 703.
-
Divide that answer by your height in inches (there are 12 inches in 1 foot).
-
Divide that answer by your height in inches again.
For example, a person who weighs 180 lbs. and is 5 feet and 5 inches tall (65 inches) would calculate their BMI as:
-
180 x 703 = 126,540
-
126,540 / 65 = 1,946.769
-
1,946.769 / 65 = 29.95
Their BMI would be 29.9.
The BMI calculation is the same for adult men and women. The BMI calculator for children is different.
What is a normal BMI?
A healthy BMI range for an adult is 18.5 to 24.9. “Normal” is only a word that reflects where your BMI is on the chart. Your healthcare provider will help you understand your health and any changes you may need to make.
Multiply your weight in pounds by 703.
For example, a person who weighs 180 lbs. and is 5 feet and 5 inches tall (65 inches) would calculate their BMI as:
-
180 x 703 = 126,540
-
126,540 / 65 = 1,946.769
-
1,946.769 / 65 = 29.95
Their BMI would be 29.9.
The BMI calculation is the same for adult men and women.
The BMI calculator for children is different.
What is a normal BMI?
A healthy BMI range for an adult is 18.5 to 24.9. “Normal” is only a word that reflects where your BMI is on the chart. Your healthcare provider will help you understand your health and any changes you may need to make.
6. Portion Sizes
If your portion sizes are too large, you can quickly gain weight – even if you’re eating primarily healthy foods. And if your foods aren’t always healthy, the weight gain from over-sized servings will be even quicker.
Portion sizes over the decades have doubled and it is showing in the growing waistlines of Americans. Studies have consistently shown that larger portion sizes tend to make people eat more food.
The portion boom, then and now:
There are several tricks and techniques to eating the portion size that’s right for you. You can start by going through your kitchen cabinets and assessing your dinnerware and serving sets for sizes and even changing the ambiance of your dining room.
By eating off of smaller plates, such as 6-inch in diameter saucer-sized plates, you will trick yourself into thinking you’re eating more than you actually are. Also, start by taking small amounts of food on your plate and remind yourself that if you are still hungry after you’re finished, you can always go back to get more.
It is also useful to cut your portion sizes in half. If your daily lunch is a huge sandwich, try cutting it in half, eating one half and waiting a few minutes. This will give your body time to receive a full sensation. You may even decide you’re not hungry enough to eat the other half.
7. Obesity as a Symptom
If you’re inexplicably gaining weight, it could be a signal of another health problem. The following conditions, for instance, can cause weight gain as a symptom of a larger underlying problem:
If you’ve had unexplained weight gain, make an appointment to see your doctor to rule out an underlying disorder.
8. Pollution
Pollutants are all around us, many of which have an influence on your delicate hormonal and metabolic systems. Among them, endocrine-disrupting chemicals, such as bisphenol-A (BPA), pesticides, PBDEs, and others can predispose you to being fat.
Frederick vom Saal, professor of biological sciences in MU's College of Arts and Science, told Science Daily:
"Certain environmental substances called endocrine-disrupting chemicals can change the functioning of a fetus's genes, altering a baby's metabolic system and predisposing him or her to obesity.
This individual could eat the same thing and exercise the same amount as someone with a normal metabolic system, but he or she would become obese, while the other person remained thin. This is a serious problem because obesity puts people at risk for other problems, including cancer, diabetes, cardiovascular disease and hypertension."
Vom Saal pointed out that out of the approximately 55,000 manmade chemicals in use in the world, 1,000 may be endocrine disrupters.
To cut down on your exposure to endocrine disrupting chemicals, avoid Polycarbonate, Lexan and Polysulfone plastics, which contain BPA, and instead use your own personal reusable water bottle made of HDPE (high density polyethylene) plastic, which is BPA-free! For example the "Wellness H2.0" portable water bottle features a unique filtration system that not only purifies ordinary tap water, but also enhances the water for better absorption and hydration.
Because household items like cleaning products, toiletries (fragrances, hairspray, deodorants, shampoos, etc.), air fresheners, paint, bug sprays and many others are major contributors to the toxins in your home, seeking out natural varieties of these items is essential.
Also, because indoor air can be two to 100 times MORE polluted than outdoor air, according to the EPA, having a high-quality air purifier is now as essential as having locks on your doors. A simple way to keep your home’s air clean and safe is by using an Air Treatment System, which uses photocatalysis designed to oxidize organic odors, germs, and fungi to create clean, pure air in your home. Ask your practitioner what air treatments system they use and recommend for the best home and office air quality?
9. A Virus?
Studies suggest that an adenovirus called AD-36 may be involved in some cases of obesity. There are more than 50 types of adenoviruses that cause illnesses such as the common cold and gastroenteritis. Typically, the illnesses are not serious and resolve on their own.
However, research shows that 33 percent of obese adults have contracted AD-36 at some point in their lives, compared to just 11 percent of lean people. Further, in 2007 it was found that AD-36 could turn adult stem cells from fat tissue into fat cells.
According to Nikhil Dhurandhar, of Pennington Biomedical Research Center in Louisiana, the virus likely triggers obesity when it spreads to other parts of your body.
A person exposed to the virus may recover from the related cough, cold or sore throat relatively quickly, but could reportedly gain weight for a period of three months, until their body has built up resistance to the virus. People with the virus could also remain contagious for three months.
“When we lose twenty pounds ... we may be losing the twenty best pounds we have! We may be losing the pounds that contain our genius, our humanity, our love and honesty.”
~Woody Allen
Click here to make an appointment
Sources
Harvard.edu
Stanford.edu
Endocrinology Advisor Factsheets glp-1 drug interactions
Cleveland Clinic
Good RX How Do GLP-1s Affect Your Sleep?
University of Chicago Medical Center
International Journal of Obesity
ScienceDaily.com
Current Opinion in Obstetrics and Gynecology;14(6):601-6.
American Academy of Child & Adolescent Psychiatry
American Journal of Physiology;285(1):R271-3.
Archives of General Psychiatry;67(3):220-229.
MedicalNewsToday.com
ScienceDaily.com
ConsumerReports.org
