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Ask Dr. Mike: What's Causing Your Rapid Weight Gain?

Here you'll find the answers to a wealth of health and wellness questions posed by Healthy Talk fans. Listen in because what you know helps ensure healthy choices you can live with. Today on Healthy Talk, you wanted to know:

A year and a half ago, I gained 25 pounds over a two to three month period. Every week, I was gaining two pounds. Then all of a sudden it stopped but the weight stayed. At that time I did not change my eating habits, there was no stress, etc., and nothing happened that could explain the weight gain. I've never had weight problems in my whole life before that. Would you know what has happened?

Rapid weight gain that seems to come out of nowhere and drastically increases over a period of two to three months can be from a handful of reasons. Usually doctors will want to know if anything has changed (in your diet or lifestyle habits) throughout those two months. Dr. Mike wants to list off some possibilities to bring up to your doctor:

  • Pregnancy
  • Low thyroid
  • Dysthymia
  • Diabetes
  • Menopause
  • Cushings disease
  • Polycystic ovarian disease
  • Liver disease
  • Pituitary issue
  • Heart failure
If you have a health question or concern, Dr. Mike encourages you to write him at This email address is being protected from spambots. You need JavaScript enabled to view it. so he can provide you with support and helpful advice.

RadioMD Presents:Healthy Talk | Original Air Date: February 16, 2015
Host: Michael Smith, MD

Dr. Mike: Okay, first question. I’m going to spend some time with this one because there’s a lot here. Let me just get into it. “Hi Dr. Smith, a year and a half ago I gained 25 pounds over a 2-3 month period. Every week, I was gaining 2 pounds. Then all of a sudden it stopped, but the weight stayed. At that time I did not change my eating habits, there was no more stress, etc… Nothing happened during that time to explain my weight gain. I had never had weight problems in my whole life before that. Would you know what has happened? What are the possible suspects?” She says: “Thank you so much. Looking forward to your help, Barbara Russ.”

If I can just summarize what’s going on here, there was weight gain. Pretty quick weight gain over a 2-3 month period and no one can really give you any answers, right? This is what we would call acute weight gain. In medicine, when faced with something like this, you know how when you do anything in life, you’re starting a new project or a new charity or a new ministry, whatever it is, you have a brainstorming session? Maybe with yourself or groups of people, whatever it is, and you start listing out things, listing out ideas. In medicine we do the same thing, Barbara. It’s called a differential diagnosis. It’s just a list of the possibilities. You create this list and from there, you start doing your best to weed out some of those choices. Let’s do that together right now. Let’s make a differential diagnosis list for acute weight gain. I’m just going to start listing them all. Some of the things are obvious and probably not what you’re dealing with, but you just list it and get it all out there.

The first, most common reason for weight gain is pregnancy. I’m going to assume that you would know that. I guess you can’t always make that assumption. I’ve seen some of those TV shows where people didn’t know they were pregnant, but I think most people know. I’m going to list that, then take it off the list. Pregnancy is the number 1 thing, but we are going to take it off the list because it’s easy to test.

Number 2 would be low thyroid. This can happen for a variety of reasons: There could be an infection in the thyroid, for instance, it could be an auto-immune attack on the thyroid, but you can knock out thyroid production pretty quickly. When that happens, you will gain weight. Why? Because the thyroid is the metabolic throttle. It runs your metabolism. If, all of a sudden, the amount of thyroid hormone decreases over a short period of time, quickly, that can cause some weight gain. That would be number 2, after pregnancy.

Number 3 on the list of acute weight gain is something called dysthymia. This is kind of like bi-polar disorder, where people have depression, then cycle to being really anxious and having lots of energy, then cycle back to depression. You have those two sides, or poles. Dysthymia is kind of like that but it’s not as bad. Dysthymia is cycling through a little bit of depression, maybe feeling a little blue, and then you cycle out of it and then back. That’s called dysthymia. It’s not as bad as bi-polar disorder, but it’s been known to cause acute weight gain. If you’re dealing with those kind of mood fluctuations, Barbara, that might be something to talk to your doctor about.

Dr. Mike: Diabetes can be associated with acute weight gain. You don’t see it too often, but it can. If you’re not maintaining your sugar level well and your insulin is getting all messed up, that can cause sugars to turn into triglycerides. That can build body fat. That can also be a potential reason. So far we have pregnancy, low thyroid, dysthymia, and diabetes.

Fifth on this list would be menopause. Menopause is not like a light switch. It’s not like: The light is on; you’re menstruating, ovulating, and all that. Then all of a sudden, one day, it just turns off. That’s not how it works. Men don’t know this, but all women know what I’m saying. It’s a process. Actually, before you hit full-blown menopause we call that perimenopausal or premenopausal. That can last years for some women. For some women it is only a few months. For some women it’s many years. For the women that experience perimenopause or premenopause over a very short period of time often can have some weight gain. So maybe we need to look at your estrogen levels, your progesterone levels, and your prolactin levels. Those are all your FSH levels and can be very important in seeing where you’re at in this part of life. That would be number 5.

Number 6 is something called Cushing’s disease. This is where you have high cortisol levels because you have a benign tumor that dumping out a lot of cortisol in your system. Cushing’s disorder, you might want to get your cortisol levels checked.

Next would be polycystic ovarian disease. When you have a lot of cysts in your ovaries it can cause something known as estrogen dominance. That means you are producing lots of estrogen but you are not producing a lot of progesterone to counterbalance it. Estrogen is a tissue builder. Estrogen’s role in a woman, for the most part, is to prepare you for pregnancy. It builds of the endometrium. It builds up the breast tissue. It develops the egg. If you have a lot of cysts in the ovaries sometimes you can over produce estrogen, you can over produce tissue build up and that can cause acute weight gain.

Number 8 would be liver disease. Sometimes, if you are gaining a lot of weight very quickly, it could be an engorged liver; what we call a fatty liver. As a radiologist, I’ve seen a lot of fatty livers on CAT scans. Most of the time people don’t even know they have it. It can be cause by alcohol, but there is also non-alcoholic fatty liver. If the liver is engorged that can cause you to put some weight on and there are a variety of reasons for that.

Next would be pituitary issues. The pituitary gland produces things like growth hormone and stuff like that. If there is a benign tumor in the pituitary gland excreting hormones that can cause acute weight gain.

Last on the list, because most people know if they have a history of it, is heart failure. If your heart isn’t working your fluid retention goes up, you get swollen, that kind of stuff. That can cause acute weight gain.

Dr. Mike: So, Pregnancy, low thyroid, dysthymia, diabetes, menopause, Cushing’s, cysts on the ovaries, liver disease, pituitary, and heart failure. That would be a nice list to work from, Barbara. So what would be your work up, then? How would I approach this after I made my list? The first thing would be to check all the hormones. I would do a good female hormone panel. Not just looking at estrogen, looking at all of it: Thyroid, estrogen, progesterone, all of that stuff. I would even look at growth hormone and prolactin, the pituitary hormones. I might test you for diabetes; maybe does a glucose tolerance test. Then I’d do an ultrasound looking at your ovaries, liver, and your heart to get a good picture if it’s anything internal, structurally, going on.

That’s how I would approach acute weight gain. Start with the differential diagnosis. I gave you a nice list, Barbara. Follow-up on some of those suggestions and please, check with your own doctor on this. Take that list in to your own doctor and see what he or she says. Hopefully that will help. This is Healthy Talk on RadioMD. I’m Dr. Mike, stay well.