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Is It Possible to Boost Metabolism After Antidepressant Gain?

Despite the popularity of this drug class, unanswered questions remain.

Key points

  • Some people may struggle with returning to pre-treatment weight after they stop taking antidepressants.
  • Reasons for consideration include sleep pattern changes, food intake, and decreased muscle mass.
  • Starting a new type of physical activity may help accelerate weight loss.

“Why can’t I lose the weight I gained on my antidepressant?”

This question is asked frequently by formerly normal-weight individuals who, to their chagrin and dismay, find their weight increased by 5 to 40 pounds (or more) after treatment with antidepressants.

They assumed that once they had ceased treatment, the weight would fall off. After all, the drug(s) which seemed to hijack their appetite and run away with it, was now out of their bodies. Their eating returned to its healthy, appropriate caloric level, and they had resumed exercising. So why did the numbers on the scale refuse to move downward?

To be sure, many do find themselves able to return to a pre-treatment weight, and although the possibility of regaining that weight should they have to start another antidepressant treatment regimen is something they worry about, for now they are pleased to find themselves at their former size.

But for some, this doesn’t happen. The 10 or 30 pounds gained a few years ago on the antidepressant are still there. Diets are tried, both the fads and the conventional. A few pounds may be lost, but they are insignificant given the amount that the individual wants to lose. Exercise regimens are begun and followed, although sometimes this is frustrating because the extra pounds make exercise difficult and often less enjoyable.

“When I was my usual normal weight, I loved going to the gym. But now that I am 35 pounds heavier than I have ever been in my life, I find it difficult to run on the treadmill and it's impossible to keep up in a spin class.“ This description of the effect of her antidepressant weight gain on her comfort in exercising was told to me by one of my weight loss clients. Her experience is similar to all too many who are “wearing” the side effects of their antidepressant treatment, months after it stopped.

The question that arises is whether antidepressants may somehow affect metabolism, such that fewer calories are needed for energy. And if this is a possibility, what can be done about it? (But at present there is no evidence that this is the cause of failure to lose weight.)

Figuring out what will enable weight to be lost may be a matter of analyzing different aspects of the dieter’s current lifestyle. For example, have sleep patterns changed? Less restless sleep or fewer nighttime awakenings may mean a small decrease in calorie expenditure during the night. This doesn’t mean that insomnia is the solution to weight loss, but it is worth noticing if this has changed at all.

Food intake should be scrutinized carefully in order to detect some causal, mindless snacking. This should be done in order to detect the consumption of calories that might slow down weight loss. It is unlikely that this will be the reason weight is so hard to lose, because those seriously concerned about their inability to lose weight will be conscious of what and how much they are eating. However, it is worth checking anyway. Some diet plans claim that it is unnecessary to be concerned about portion sizes or calories. Often they state that weight will be lost because entire food groups, such as carbohydrates, are eliminated or that certain foods are so low in calories, large amounts can be eaten. However, calories do count, even when they come from low-calorie foods or from foods deemed acceptable to the weight loss program.

Decreased muscle mass may be another factor contributing to the glacial slowness of the weight-loss efforts. If physical activity declined during the depressive episode, muscle loss may have resulted. This might account, at least in part, for difficulty in losing weight. According to an article on physical activity and energy utilization, most of the calories that our bodies use go toward physical activity. This is not limited to obvious exercise, but even the smallest muscle movement, i.e., blinking our eyes or wiggling a toe. It is thought that every pound of muscle burns about six calories per day at rest. In comparison, a pound of fat burns about two calories a day when the body is at rest. Of course, when the body is in motion, caloric expenditure increases significantly. Interestingly, the well-trained athlete will burn fewer calories than the newbie running or biking the same distance.

Perhaps one technique for disposing of more calories, in the interest of losing weight, is to start a new type of physical activity. If the frustrated dieter exercises regularly but does not see any significant weight loss as a result, he or she might consider switching to another type of exercise. If a well-trained runner starts swimming as a new activity, or vice versa, he or she might struggle to reach the same level of ease and skill in the different sport. During this early phase of training, more calories may be utilized per unit time than during the exercise in which the dieter is well trained. Increasing muscle mass is another obvious way of possibly accelerating weight loss, although unless one wants to become a bodybuilder, there is a practical limit to how bulked up one wants to become.

But these suggestions may not accomplish the weight loss sought. The dieter may still find his or her body resistant to releasing the pounds gained as a side effect of antidepressant treatment. Persistence and patience must be summoned so that the dieter will continue to eat healthfully and engage in frequent physical activity, and wait for results. Eventually, the pounds should come off. There is plenty of evidence from natural and political catastrophes that no one is immune from weight loss when food supply is at starvation levels, combined with excessive manual labor. However, no one is suggesting this as a solution to the weight problem.

Two questions remain unanswered:

Why not prevent the weight gain initially when the patient begins treatment with the antidepressants?

What is the reason it takes so long to lose the weight after withdrawal of antidepressants?