Weight gain and antidepressants

Many of Health24's users ask me if the antidepressants they are taking, could be linked to weight gain. A recent article on “Weight gain caused by antidepressants” by Dr Ian Westmore which was published in the August Edition of the Medical Chronicle, sheds more light on this tricky question.

On the one hand, patients suffering from severe depression require medication to assist them to cope with their problem and to prevent extreme reactions such as suicide, while on the other hand many of these medications can cause pronounced weight gain which will in turn contribute to increased depression and lack of self confidence in the affected patients.

Different antidepressants and their effects

Dr Westmore states that, “Weight gain can occur in up to 25% of patients taking antidepressants”. According to this author, the so-called tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) are the most likely antidepressant medications to cause weight gain, while selective serotonin reuptake inhibitors (SSRIs) are less likely to have this negative effect on weight.

In some cases, patients using SSRIs may actually lose a small amount of weight at the start of their treatment (usually only about 0,5 kg), but then go on to gain, rather than to lose weight.

A complex picture

Some patients suffering from severe depression lose a great deal of weight, so that when they receive treatment with antidepressants and gain some weight, this may actually be a sign of an improvement in their clinical picture. But the majority of patients with major depressive disorder gain more weight than desired. Dr Westmore attributes this to various factors:

  • seeking comfort in food which leads to overeating
  • the effects of antidepressants such as TCAs. One study showed that TCAs stimulated appetite and increased carbohydrate cravings causing gains varying between 0.57 to 1.37 kg per month during treatment.

(Westmore, 2010)

Why do antidepressants cause weight gain?

Dr Westmore says that there are a number of theories that have been put forward to try and explain why antidepressants in general have the effect of causing weight gain.

Antidepressants may have the following effects that contribute to increased body weight:

  • stimulation of appetite (TCAs)
  • increased carbohydrate cravings (TCAs)
  • interference with central nervous system functions that regulate energy balance
  • changes in the Resting Metabolic Rate (TCAs, SSRIs, MAOIs)
  • interaction with a genetic predisposition to weight gain
  • counteracting the action of the 5-HT2 receptors, which will then increases appetite 
  • interference with the production of noradrenaline

(Westmore, 2010)

Appetite regulation and weight gain or loss, are very complex reactions which are influenced by a wide variety of hormones and compounds, all of which may be negatively affected by medications such as antidepressants.

Solutions to antidepressant weight gain

The following solutions are suggested to combat weight gain which may occur when antidepressants are prescribed:

Things to do:

  • Always discuss any changes you notice in your body weight when you are being treated with antidepressants with the prescribing doctor. The doctor may be able to adjust your dosage or change your prescription to another antidepressant which is better suited to your unique metabolism and requirements.
  • If you are turning to food as ‘comfort’, ask your doctor to refer you to a clinical psychologist who will teach you better methods of coping with your depression.
  • Consult a registered dietitian to assist you with a balanced slimming diet that is tailored to your needs.
  • Do as much cardio or aerobic exercise as possible. This type of exercise will not only help you control your weight and promote weightloss by stimulating your metabolism, but it has a strong positive effect on your psychological makeup. Doing daily exercise is also an expression of taking back control of your life despite being depressed, which can be an empowering experience.


Things to avoid:

  • Never stop your antidepressants without first discussing this step with the medical doctor who is treating you for your depression. It can be dangerous and even fatal to stop taking antidepressants if you suffer from severe depression because the danger of suicide is increased if you should abruptly stop your medication.
  • Do not take over-the-counter slimming pills or fat-burners or any other herbal or pharmaceutical product that is advertised as a ‘sure-fire solution to rapid weightloss’ because many of these herbal products can interfere with your antidepressant treatment and even counteract the effect of your antidepressants leading to serious side-effects.
  • Do not use starvation diets to try and achieve rapid weightloss because very-low-energy diets have been linked to an increase in depression.
  • Never take antidepressants for the sole purpose of losing weight. Some of my Readers have reported this disturbing practice which should be prevented at all costs.

 Healthy diets

A healthy, balanced low-fat, moderately-energy-reduced diet that includes all the food groups will ensure that you can either prevent further weight gain or achieve steady weight loss despite using antidepressants.
Certain patients will benefit from using a low-fat, low-glycaemic index (GI) diet to control their weight. If you are not losing weight on a standard low-fat diet ask your doctor to check if you suffer from insulin resistance.
Patients with insulin resistance respond more readily to a combination of low-fat and low-GI foods. Because low-GI diets are tricky to get used to, it is always a good idea to see a registered dietician who will provide you with an individual diet prescription and also guide you through the initial phases of getting used to your low-fat, low-GI diet. Visit the Association for Dietetics in SA website and click on "Find a Dietician" to find a dietician in your area.

Even when losing weight, you need to eat some foods from each one of the foods groups listed below every day to guarantee that you don’t develop deficiencies which can make you feel even more depressed:

  • Low-fat dairy products (milk, yoghurt, cottage cheese, maas) are our best source of readily available calcium in the diet. Calcium is essential for bone health and nerve impulse conduction. Have 3 servings a day. 1 serving = 1 cup of milk/yoghurt/maas; ½ cup cottage cheese.
  • Fresh fruit and vegetables are rich in phytonutrients and dietary fibre which protect us against a variety of diseases and keep your digestion regular. Have at least 5 servings a day. 1 serving = ½ to 1 fruit, ½ cup cooked vegetables/salad.
  • Low-GI grains and cereals (e.g. low-GI breads, high-fibre breakfast cereals, wholewheat crackers, brown rice and wholewheat pasta) are low in fat and high in fibre and vitamin B complex (the latter vitamins are essential for your nervous system). Have 4-5 servings a day. 1 serving = 1 slice of bread; ½ cup dry or cooked cereal/rice/pasta; 3 crackers.
  • Lean meat, fish, eggs and legumes (dry, cooked or canned beans, peas, lentils and soya) are rich in protein and minerals like iron (to prevent anaemia) and zinc (to boost immunity). Have 2-3 servings a day. 1 serving = 30g meat/fish; 1 egg; ½ cup cooked legumes.
  • “Good” fats and oils like soft margarine (sold in tubs, not bricks!) made with mono- or polyunsaturated fats, and oils rich in monounsaturated and omega-3 fatty acids (olive, canola, flaxseed and avocado oils) are beneficial to the nervous system and prevent heart disease. Have 2 servings a day. 1 serving = 1 tablespoon. 

- (Dr IV van Heerden, DietDoc, October 2010)


(Westmore I (2010). Weight gain caused by antidepressants. Medical Chronicle, August 2010, p. 75.)

Any questions? Ask DietDoc

Read more:

Depression and antidepressants

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