Hidden causes of weight gain: If you're doing everything right but still gaining weight, a medical problem could be to blame. Here, five frequently missed culprits behind excess pounds - Health

Shape, May, 2002 by Catherine Clifford

If the needle on your bathroom scale starts creeping upward, or refuses to head downward, you'll probably suspect the cause is too many doughnuts, not diseases or drugs. But while the usual culprits -- too much food, too little exercise -- do account for most excess poundage, there are some surprisingly common medical conditions and widely used prescriptions that can add anywhere from a little to a lot -- a whole lot -- of excess weight. Here is a checklist of what to watch for if you inexplicably find fat either packing on or unwilling to pack up and go.

1. Hormonal havoc

You'd think 40 or more extra pounds would be a clue that something's amiss. Yet many of the 7-10 percent of pre-menopausal women with polycystic ovary syndrome (PCOS) often go for years unaware that their weight gain is in part due to this underdiagnosed condition, in which the ovaries and sometimes the adrenal glands, for unknown reasons, pump out too much male hormone, according to Andrea Dunaif, M.D., chief of endocrinology at Northwestern Memorial Hospital and professor of metabolism and molecular medicine at Northwestern university Medical School. Because the pounds typically pile on gradually beginning around puberty, or sometimes don't surface until post-pregnancy weight refuses to budge, it's frequently not obvious to PCOS sufferers, or their doctors, that there's a medical trigger. Possible tip-offs: thinning hair, excess facial hair, severe acne, irregular periods, impaired fertility -- all hallmarks of excess male hormone.

It's not the extra male hormone that triggers the weight gain, though. So what does? Short answer: Nobody knows, Dunaif says. While there seems to be a genetic component to PCOS -- it runs in families -- and a genetic component to the associated weight gain, there's little to explain why some of those diagnosed develop weight problems while others do not. It is clear that cultural and environmental factors play a part because Europeans, and Americans on the coasts, who may feel more social pressure to be skinny, gain much less weight on average than do their (sometimes literal) sisters in middle America. The encouraging side of this is that while many women with PCOS feel like their weight is an immovable number (and treatment for PCOS does not help with weight loss), studies show that almost any woman with PCOS, treated or not, can, if put on a supervised diet and exercise program, lose 10 percent or more of body weight, Dunaif notes. Dropping such a moderate amount of weight often will, in turn, push male hormone levels down, leading to a resumption of regular periods and improved chances of conception.

2. Thicker from thyroid?

For the most part, blaming a sluggish thyroid for excess weight falls in the "you wish" category. "A lot of overweight people sort of hope they have hypothyroidism because it's treatable," comments Howard Eisensen, M.D., director of Duke University's Diet and Fitness Center. "But it's rare to find someone who's significantly overweight because of an underactive thyroid. Even if there is decreased thyroid function, correcting it doesn't do much to correct overweight because it doesn't cause much gain to begin with." If weight creep is on a small scale -- in the 5- to 10-pound ballpark -- it's possible that hypothyroidism is behind it, though. If you have other telltale symptoms, such as brittle hair and nails, dry skin and a tendency to feel cold, definitely get checked out. If your thyroid is to blame, treatment should shrink you a bit, but not because of much fat loss.

Another name for hypothyroidism is "myxedema," which describes a kind of swelling from thick fluidlike tissue that is a hallmark of chronic low thyroid, explains George Bray, M.D., Boyd Professor at Louisiana State University. Most of thyroid-prompted weight gain, therefore, is actually due to excess fluid, not fat; correcting the thyroid problem banishes soggy tissue, along with its poundage, pretty effectively.

3. The weight of water

As Bray points out, extra pounds don't always equal fat, but are sometimes due to fluid retention -- familiar to most women from premenstrual symptoms. If puffiness isn't related to the menstrual cycle, though, it shouldn't be ignored. "If someone's retaining a lot of water -- enough to add more than a couple of pounds -- they'd better get to their physician very quickly to make sure they don't have heart or kidney failure, both of which can cause edema, or swelling," cautions Robert Berkowitz, M.D., medical director of the university of Pennsylvania Weight and Eating Disorders Program, though he adds that such problems are much more likely to afflict older women. "If you push a fingertip into your skin and it leaves a real indentation rather than springing back, that's a tip-off that it's fluid, not fat." Other symptoms include shortness of breath (congestive heart disease), decreased urine output and loss of appetite (kidney failure), and fatigue and increased abdominal girth even without weight gain, for b oth. Liver disease and certain cancers can cause abnormal fluid accumulation in the abdomen as well, so any big boost in your waist size, with or without weight gain, warrants a look by your doctor, Eisensen advises.