You know who you are. You’ve been eating stable portions of pretty much the same healthy food for years and you consider yourself weight conscious. Long ago you decided that by combining smart food choices and a health club membership, you were not–definitely not–going to be one of those people who added a point or two to their BMI score every year.
Speaking of your BMI, you’ve been in the normal range for years, but feeling a bit pudgy you entered your weight and height into a BMI calculator and audibly gasped at seeing yourself a hairsbreadth below overweight. You started watching everything you put in your mouth and added another weekly workout. Then, virtually overnight, you were up another ten pounds, your BMI solidly entrenched in the overweight range, the dreaded obese looming on the horizon.
Of course you didn’t have to bother with your BMI to know something was wrong. The waistbands of your clothes are maxed out and you regularly unbutton pants and skirts, covering the gap with attractive untucked tops. You’ve shamefully buried those $200 designer jeans in the depths of your closet. And the worst sign? Your grandmother thinks you finally look healthy, except she grew up half-starved in Eastern Europe where the only signs of good health were being well-rounded and having good teeth.
So why are you gaining weight?
If you know for certain that your eating habits and activity levels are unchanged, what’s happening? Here’s a list of possibilities. Importantly, the causes listed here for weight gain are not uncommon. In a typical week at the office, I see at least three or four patients who write the phrase “I can’t understand why I’m gaining weight” as their reason for visiting.
An astonishing 10 to15% of all weight gain issues can be traced to some of the most widely used medications prescribed in the US. The most common sentence I hear from patients who learn their daily medication may be the villain: “But the doctor never told me weight gain was a side effect.”
Here are the usual suspects:
- SSRI antidepressants Prozac (fluoxetine), Celexa (citalopram), Lexapro (escitalopram), Luvox (fluvoxamine), Paxil (paroxetine), and Zoloft (sertraline). Bear in mind that depression itself is associated with weight gain (craving high-carbohydrate comfort foods combined with inactivity), but these medications have been shown to both increase appetite and change the way your body breaks down calories.
- Mood stabilizers Risperdal (risperidone), Seroquel (quetiapine), Zyprexa (olanzapine), Clozaril (clozapine), and lithium. All turn your appetite switch to high and leave it stuck there, even after you’ve polished off a large Lou Malnati pizza.
- Diabetes meds Glucotrol, DiaBeta, Actos, and insulin. For many people, already overweight from Type 2 diabetes, these drugs vacuum calories into fat cells where they’re stored for future energy needs (and never burned up).
- Corticosteroids Any form–pills, ointments, nasal sprays–increases appetite and fat storage.
- Meds for seizures, migraines, and chronic pain Depakote, Elavil (amitriptyline), and Lyrica (pregabalin) all increase appetite and slow metabolism. Lyrica is heavily promoted for fibromyalgia even though most fibro patients are already overweight from inactivity.
- Beta blockers Propranolol (Inderal) and atenolol (Tenormin) reduce your body’s reaction to exercise so you work out but never get a cardio response.
- Antihistamines Zyrtec, Benadryl, Allegra, and Claritin.
You’re hypothyroid (or have untreated Hashimoto’s disease)
Even minimally underactive thyroid function slows down everything in your body, so you eat but don’t burn that food for energy. Instead, excess calories are shunted into fat cells.
The blood test commonly used to screen for hypothyroidism, TSH, only picks up fairly severe disease. More accurate tests include Free T3, Free T4, Reverse T3, and basal temperature testing. Your basal body temperature, which measures your body temperature when you emerge from sleep, is a good screening test for mild low thyroid. Here’s how to perform this test at home.
Keep in mind that the TSH (often the only thyroid test doctors order) returns normal results for TSH readings under 5.0, though patients frequently have symptoms of thyroid underactivity between 2.5 and 5.0. Most people feel their thyroid best when TSH is between 1.0 and 2.0.
Hashimoto’s is a common autoimmune disease that mainly affects your thyroid gland and is the commonest cause of hypothyroidism (underactive thyroid). Most conventional physicians don’t test for Hashi’s until the patient is already hypothyroid (TSH over 5.0). But in actual fact, the Hashimoto antibodies might have been present for years, slowly reducing thyroid function. Some doctors, especially in Europe, routinely test for Hashi antibodies and start the patient on thyroid hormone before TSH starts to rise.
You’ve got SIBO (small intestine bacterial overgrowth)
With this fairly common digestive condition, excess bacteria in your small intestine produce two gasses, methane and hydrogen. We now know that methane slows down the intestines. The meal you just finished remains sluggishly stuck in your intestines and your body thinks it needs to absorb more calories from it. When you think “my dinner feels like it’s just sitting there,” (a) you’re probably right and (b) you’re absorbing more calories than your thin friend sitting across the table.
SIBO and hypothyroidism go hand-in-hand. When you have low thyroid, your intestines slow down and you absorb more food. Your sluggish intestines lead to SIBO and methane production so the intestines slow down still more, and you absorb even more food. And then you wonder why you’re gaining weight.
You’ve got other hormonal issues
PCOS (polycystic ovary syndrome) is an extremely common hormone abnormality in which a woman’s ovaries, for unknown reasons, start to pump out too much of the male hormone testosterone. This condition is often overlooked by primary care doctors (ob-gyns usually diagnose PCOS). Telltale signs of PCOS include thinning hair, excess facial hair, acne, irregular periods, impaired fertility, and, of course weight gain.
Cushing’s syndrome Up in the medication section I mentioned that using corticosteroids in any form can lead to weight gain. In Cushing’s syndrome, fortunately uncommon, there’s a non-cancerous tumor on the adrenal gland itself, pumping out bucketsful of cortisone (which produces the same effect as corticosteroid drugs). People with Cushing’s become obese so quickly that their skin develops stretch marks. Once the tumor is surgically removed, the situation reverses itself.
You’ve developed hidden food sensitivities
When you’re sensitive to one of the Big Six (dairy, egg, corn, gluten grains, citrus, and soy), you’ll likely retain a lot of fluid every time you indulge. Elson Haas, MD, a nutritionally oriented physician in California, wrote about this condition in his book The False Fat Diet. He added sugar and peanuts to the Big Six and called the weight gain “false fat” because the weight was due to chronically stored fluid.
There are two ways to determine if your extra weight is water or fat. You can schedule with one of our nutritionists and she’ll test you for percentage of body fat and water. Alternatively, for at least three weeks assiduously eliminate everything Dr. Haas lists in his book. If at the end of your test period you feel simply great and are down 15 to 20 pounds, then a lot of your avoirdupois was indeed false fat.
Good luck with this. I know the sudden onset of mystery pounds can be very frustrating. If you’re in the Chicago area and need some help, you can start with our Nurse Practitioner Maureen Milota or our physicians including me. Our nutritionists (Marcy Kirshenbaum, Marla Feingold and Seanna Tully) and acupuncturists (Mari Stecker, Cindy Kudelka and Helen Strietelmeier) are here to assist as well.
David Edelberg, MD
12 thoughts on “The Mystery Of Sudden Weight Gain”
The point of view of your article has taught me a lot, and I already know how to improve the paper on gate.oi, thank you.
I ben gaining weight due to over the head stress levels. I also retain a lot of water for a long time.
Hi Dr. E, can you explain how antihistamines are part of weight gain? Thanks.
I am turning 53 this month. Last period/menopause began in December 2012. Since then I have gained 12-15 lbs predominantly in belly. Despite eating well and exercising I cannot lose more than 2-3 lbs. Recent blood lab results for thyroid are likely incomplete and deemed “normal”. Results were Oct 2015: TSH 4.26 (flag reference 0.350-5.000) and then May 2016: TSH W/REFLEX TO FT4 3.91
I will record my Basal Temp for next 5 days as per your recommendation. I feel as if I have been “brushed off” by my GP and OBGYN in this regard. I believe my healthcare options need a change. Thank you.
Hi Joan – Very sorry to hear all of this, particularly the part of being brushed off by the folks you turn to for help. Any chance you’re in the Chicagoland area and we might be of service? If not, please reply to this and let me know where you are. I’ll try to make some recommendations for healthcare resources.
Thabnk you! This is very helpful for me as I’m trying to manage my post chemo/radiation/throidectomy meds for the best effect with the fewest negative side effects.
An estimated 50 million people in America suffer from hay fever and other allergies but if they take antihistamines, such as cetirizine (Zyrtec) and fexofenadine (Allegra), they are more likely to be overweight and have higher insulin concentrations.
According to a 2010 study, men and women on antihistamines weighed on average of 9.5 pounds and 4.4 pounds more, respectively, than controls.
Why? The drugs target the H1 histamine receptor, which besides its role in allergen response, is part of the brain’s appetite satiety circuitry. Suppression of this receptor’s activity can stimulate appetite.
I’ve been battling this without success, simply not knowing how to find a healthcare practitioner that is knowledgeable on these issues and is sensitive enough to test for them, rather than merely shifting the weight blame as a personality flaw.
How do we find such mensches in scrubs outside of the Chicago area?
Hi Jill – You can google Institute for Functional Medicine for other like-minded physicians in your area that could help,
Hope this helps!
I understand the steroid-weight gain relationship (and had lots of steroids during my lung cancer treatment) but please explain the antihistamine-weight relationship. Thank you.
I gained weight a long time ago when I was put on Antibiotics. I haven’t been able to lose that weight since.
Hi Victoria – This may point to what Dr. Edelberg wrote about SIBO (small intestine bacterial overgrowth syndrome). Finding a primary care practitioner to help with restoring normal digestive health may be useful. If you’re in the Chicago area, Dr. Edelberg, our Nurse Practitioner or I would be happy to see you for this. Best of luck to you. Such a frustrating problem.
Sincerely, Dr. M