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Weight Loss

Weight-loss supplements – the expert verdict

Truth about weight loss supplements MAIN

Weight loss supplements are a minefield of inflated claims. So how do we know what to believe? Olivia Hartland-Robbins looks at the science and asks the experts 

Supplements, glorious supplements. Well, they might not always be as glorious as they claim to be.

Recent news revealed that a US regulator has fined an Amazon firm $12.8 million for fake reviews of a weight loss supplement.

The weight loss supplement in question claimed that it ‘literally blocks fat’.

So, we wanted to know – and we’re sure you would too – how can we tell what’s fake and what isn’t?

‘Supplements stating they can actively promote weight loss, without mentioning the need to address other factors, should probably be avoided,’ says Nutritional Therapist Ellie Isom (BSc Hons, MSc, mBANT, CNHC) from the Clinical Nutrition Team at BioCare.

Isom further warns that we should be especially wary of products that claim they can help us to lose a certain amount of weight.

Anything that looks too good to be true or claims amazing results like ‘lose a stone in a week by taking this pill’ or claims to include a so-called miraculous ingredient that you haven’t heard of should be steered clear of, she advises.

With so many weight-loss supplements, what’s the expert verdict on popular weight loss boosting supplements out there today?

Fat blockers – beware

Supplements that are popular but still up for debate are ‘fat blockers’. These often come with unpleasant side effects, such as diarrhoea, because they cause unabsorbed fat to build up in the bowel, Isom explains.

Although these ‘fat blockers’ may work in the short run, if you are experiencing symptoms like diarrhoea then you are probably only losing weight because you are going to the toilet more often – and you don’t need an expert to tell you that isn’t healthy or sustainable.

‘Fat is important in our bodies, especially essential fats, such as omega-3 and omega-6,’ says Isom.

‘These fats are used within our body for so many processes including the production of hormones and anti-inflammatory molecules, moisturising our skin, and supporting our cardiovascular health, to name a few.

‘Excluding fat altogether from your diet, or supplementing with fat blockers, can actually be detrimental to your overall health’.

Green tea extract – does work

Everybody has jumped on the green tea wagon and you’ll be glad to know that green tea extract as a supplementary tool for weight loss is indeed not a fad.

Green tea extract has been proven to support weight management, with research showing that supplementation does aid weight loss in overweight individuals.

In fact, in a randomized double-blind placebo-controlled clinical trial saw 50 overweight women randomly divided into two groups. Group A received dietary supplements containing 125mg green tea and group B received placebos. These were taken twice with lunch and twice with dinner every day for eight weeks.

The study found that those taking green tea supplements for eight weeks had beneficial effects on weight loss and reducing their BMI (Body Mass Index).

Further research is continuing to take place, reveals Isom, with Dr Justin Roberts from Anglia Ruskin University, who is currently conducting a study on green tea supplementation and body composition. ‘This continued research highlights further potential for beneficial effects of green tea supplementation’.


Green coffee extract – might work

There is also some research to suggest that green coffee extract may be supportive for weight management and blood glucose regulation.

However, Isom explains that the majority of the research that has been conducted has been done on animal studies. Therefore, the reliability of this research and the transferability across to humans is questionable.

A recent meta-analysis and systematic review on the use of green coffee concluded that the research may perhaps be promising, but the methodology of the studies was poor therefore further research is still required. Basically the jury’s still out on green coffee extract.

Garcinia cambogia – does work

One ingredient that is commonly seen in weight-loss supplements is garcinia cambogia. Have you heard of it?

This so-called magical fruit is a tropical species of garcinia native to Indonesia. This apparently fat-busting fruit looks like a small pumpkin and is green or pale yellow in colour.

Amazingly, there is substantial evidence regarding garcinia cambogia and the effect it can have on weight management.

Fresh Garcinia

‘Garcinia cambogia contains hydroxycitric acid, a competitive inhibitor of ATP citrate lyase, which is a key enzyme that facilitates the synthesis of fatty acids, cholesterol and triglycerides,’ explains Isom.

A study looking to evaluate the efficacy of garcinia cambogia on body weight and fat mass loss in overweight human subjects saw subjects randomized to receive either active herbal compound (containing 1500 mg hydroxycitric acid per day), or placebo, for 12 weeks.

Garcinia Cambogia Plus BioCare

Both groups were also prescribed a high-fibre, low calorie diet. Body weight was evaluated every other week and fat mass was measured at weeks 0 and 12.

Patients in both groups lost a significant amount of weight during the 12-week treatment period however there were no significant differences between treatment groups. This means that although garcinia cambogia can be beneficial for supporting weight management, modifying your diet can also be just as effective.

An added benefit of garcinia is that it can however help to amplify the satiety signal, meaning you will feel fuller for longer which will also lead to a reduction in the amount of food you eat.

‘One possible way it might do this is by increasing levels of leptin, the hormone involved in satiety,’ adds Isom. (Try BioCare’s Garcinia Cambogia Plus, £29.54) 

Conjugated Linoleic Acid (CLA) – may work

Conjugated Linoleic Acid (CLA) is a fancy name for fatty acids that are found mostly in meat and dairy. And we have some good news, CLA may actually support fat management, and has been proven to reduce fat mass in overweight individuals.

A randomised, double-blind, placebo-controlled trial saw subjects randomised to take a daily intake of 500ml milk supplemented with 3g CLA or placebo for 12 weeks.

60 healthy men and women (aged 35-65 years) with signs of the metabolic syndrome participated and results found that total fat mass in the CLA-milk sub-group decreased significantly while no changes were detected in the placebo group.


Exactly how CLA works is not currently unknown, but it may support fat management via increasing energy expenditure, suppressing fat storage and supporting blood glucose management. However controversially, CLA has also been shown to increase inflammation, which is already very prevalent in overweight individuals. That means an excessive intake of CLA may not be advisable.

‘Therefore, although supplementation with CLA could potentially support fat management, it should perhaps be used with caution’ warns Isom.

Raspberry ketones – probably don’t work

Unfortunately, despite the popularity raspberry ketones received a few years ago after US wellbeing TV mega-star Dr Mehmet Oz mentioned them in a segment on his show, there is currently a serious lack of research on raspberry ketones and weight loss.

‘The efficacy and reliability of raspberry ketones is questionable, and they are rarely recommended by registered nutritional therapists,’ says Isom.


A final note

‘Relying on supplementation alone for weight loss is not appropriate,’ confirms Isom, ‘What needs to be addressed first are the basics, your diet and lifestyle’.

‘Weight loss and even weight gain is based on factors such as energy intake and energy expenditure, which is about what and how much you are eating and how often you are exercising,’ explains Isom.

‘There are also other important factors such hormones, lifestyle, and medications that could influence weight loss’.

Isom advises that to achieve a healthy weight you should be increasing your intake of fruit, vegetables and good quality proteins such as lean meat, fish, eggs and poultry, pulses and tofu, and reducing your intake of refined sugar and carbohydrates and also ensure you’re exercising at least 30 minutes five times a week.

If you’re still not losing weight, then supplements might help but make sure you do your research and use one that is proven to work.  Even then, despite what these supplements can and can’t do, there is no quick fix to weight loss and the nutrients mentioned above should not be considered a substitute to a healthy diet and lifestyle.

They may be used as a method of supporting weight management, ‘but they will not address the initial root cause of weight gain and difficulty losing weight, and should not be used alone in an attempt to achieve successful and sustainable weight loss,’ says Isom.

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