Supplements for weight loss. Do they really work?

Do the magic pills and potions in the market, that claim to blast fat away, really achieve effective weight loss? Short answer, no. Long answer ,yes with a big BUT. Many supplements do produce short-term weight loss however it’s not a loss of fat, but fluids and/or muscle which can negatively impact health. Because there are so many products on the market, we will only discuss the two main categories of weight loss supplements: shakes and burners.

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Meal Replacement Drinks and Shakes

These are low-calorie protein drinks with added vitamins. Instead of lunch or dinner, you have a shake instead. They work by reducing your daily calorie intake. It’s that simple. If you usually consume a large, calorie-dense, nutrient poor meal, but replace it with a shake (with a quarter of the calories) of course you will lose weight.

Food Standards Australia and New Zealand (FSANZ) mandate that ‘a formulated meal replacement must contain in a serving, no less than 12g protein, 850kj and 25% of the RDI of each vitamin and mineral listed in column 1 [shown below]’.

meal replacement standards

The added vitamins are a bit of a waste, especially if the are the fat soluble kind like A, D, E and K. If you are not consuming a small amount of fat with these vitamins then the body will not absorb them. That is why they are called fat soluble. You are making expensive wee instead. The added vitamins may also not be in a bioavailable form (in a form that the body can use). Drinking a meal replacement shake is not the same as consuming a small healthy meal.

Meal replacement drinks may also contain satiating substances (ingredients that make you feel full) such as carrageenan which can cause tummy upsets in some people.

What do the studies say?

In a 2013 study on obese women, those who consumed low-calorie drinks alongside a low-calorie diet did not lose more weight than those who only ate a low-calorie diet1. They did reduce their waistline measurements more than the non-drink group, but overall weight loss was the same between groups1.

There may be also negative side effects of inducing rapid weight loss with shakes such as gallstones, hair loss, tiredness, cramps and constipation3.


Fat ‘Blaster’ or Fat ‘Burning’ Pills and Drinks

These supplements claim to ‘burn’ fat or prevent its absorption. Common main ingredients are ginseng, caffeine and ephedrine (may be listed as Bitter Orange or Country Mallow on the label). They are stimulants that increase heart rate and stimulate the nervous system4, tricking your body to think it’s run a marathon. Kind of like those post-coffee jitters, only amplified.

Detox teas or skinny teas and juices also fall into this category. There’s nothing detoxing about them, they just give you diarrhea.

What do the studies say?

Caffeine and ephedrine may have modest effects on weight loss2,4 BUT not without some side effects. Increased blood pressure and heart rate, headaches and agitation are a few of the mild negative side effects. Psychosis, stroke, heart attack and loss of consciousness are the severe side effects2. Obese consumers may be even more at risk if they are already suffering from hypertension.

Products that prevent absorption of fat lead the consumer to pass greasy, fatty stools (poo) because that unabsorbed fat has to go somewhere. As mentioned earlier, a reduction in fat absorption may also result in a reduction of vitamin uptake.

Why is there a high chance of weight regain with supplements?

After a supplement program, consumers resume their normal diet and put all the weight back on for different reasons. Supplement products do not educate the consumer about long term healthy eating behaviours or provide realistic weight loss expectations3. Also, these supplements may leave the consumer feeling hungry so they are more likely to binge after the diet, if not during the diet3.

In an analysis of 25 studies on weight-loss diets, 57 percent of people who undertook a commercial weight-loss diet were found to lose less than five percent of their initial body weight3. So if an individual weighs 100kg, they lost less than 5kg for the duration of their diet (typically a few months in commercial diets).

A healthy diet and moderate exercise will never be as sexy as a quick-fix and clever advertising. But if you want long term, sustainable and safe weight-loss, good old fruit and vegetables, lean proteins and wholegrains is the way to go.

Have you used weight loss supplements?
Share your experience in the comment box below.


*Any information provided by Food Hermetica is a guide only and should not replace medical advice. Reader discretion is advised.

*Food Hermetica is not affiliated with or endorsed by any external links found within this post. Information provided by an external link is the responsibility of the external site owner.

*Questions, compliments or complaints? Food Hermetica welcomes all constructive feedback and will endeavour to maintain a high standard of informative reporting.

  1. Alves, N., Enes, B., Martino, H., Alfenas, R & Ribeiro, S. (2013). Meal replacement based on Human Ration modulates metabolic risk factors during body weight loss: a randomised controlled trial. European Journal of Nutrition. doi: 10.1007/s00394-013.0598-3
  2. Bartels, C., & Miller, S. (2003). Dietary supplements marketed for weight loss. Nutrition in Clinical Practice, 18, 156-169
  3. McEvedy, S., Sullivan-Mort, G., McLean, S., Pascoe, M & Paxton, S. (2017). Ineffectiveness of commercial weight-loss programs for achieving modest but meaningful weight loss: Systematic review and meta-analysis. Journal of Health Psychology, 1-14. doi: 10.1177/1359105317705983
  4. Poddar, K., Kolge, S., Bezman, L., Mullin, G, & Cheskin, L. (2011). Nutraceutical supplements for weight loss: a systematic review. Nutrition in Clinical Practice, 26 (5), 539-552. doi: 10.1177/0884533611419859



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