Is losing weight your number 1 New Year’s Resolution for 2014? Australians were estimated to spend $643.7 million on weight loss counselling services, low-calorie foods and diet supplements in 2013-014 alone. Weight loss supplements promise miracle results and rapid weight loss without the need to diet or exercise with impressive before and after shots. But do their claims meet these expectations? We asked our December Sub of the Month to investigate.
About our expert:
Gemma Critchley is an accredited practising dietitian based in the UK. Gemma is passionate about putting nutrition research into context and ensuring the message doesn’t get twisted along the way. A foodie at heart who loves experimenting in the kitchen, she believes in real food before supplements. Check out her blog Dietitian without Borders, Twitter or Facebook page.
I’ve sleuthed around and found 7 of the most popular supplements to investigate for you. Do they give a weight loss edge? Are they worth paying for?
African Mango
Claim to Fame: Breakthrough weight loss fix for women over 40 claimed to reduce appetite, carbohydrate absorption and inhibit fat-converting enzymes.
What is it? The African mango is a West-African fruit from the Irvingia gabonesis tree. Traditionally eaten in West African countries like Cameroon or Nigeria, it is similar to a mango and contains an edible protein rich seed which is extracted to make the supplement.
How it ‘works’? Reported to restore leptin balance, inhibit the digestion of the enzyme amylase to reduce carb absorption, increase adiponectin hormone levels to help regulate blood sugar levels and inhibit glycerol-3-phosphate dehydrogenase to reduce the amount of glucose that is turned to fat.
Reality Check: African mango seeds are high in soluble fibre which has been associated with greater weight control and cholesterol lowering in some studies. Taking 150mg of african mango extract (IGOB131) twice daily before meals for 10 weeks resulted in 12.8kg weight loss without any changes made to diet or physical activity levels in one randomized controlled trial (1.3kg per week). Impressive, but worth noting that it was funded by a supplement manufacturer and unknown whether these short-term effects continue for longer periods or can be repeated in further studies. Julie Chen MD explains more about African Mango here.
Capsaicin
Claim to Fame: Boost the rate which fat is burnt, break down fat and ease your appetite.
What is it? Capsaicin is one of a group of compounds called capsaicinoids found in chillies responsible for their hot, spicy and burning characteristics.
How it ‘works’? Reported to increase energy expenditure by generating heat and boosting temperature, increase lipid oxidation and decrease fat stores. The presence of brown abdominal fat may play a role in the biological function of capsaicin increasing energy expenditure. Appetite reduction appears to be partly a sensory response with increased satiety observed after consumption of capsaicin.
Reality Check: A recent meta-analysis reported that capsaicinoids could reduce energy intake by 310kJ when included as part of a meal. Consumption was observed to temporarily increase energy expenditure by around 210kJ per day in a systematic review which could achieve significant weight reductions over 1-2 years. Not exactly overnight, rapid results you can read more from Diane Boyd RD Chili Peppers Health food or Hype?
Garcinia Cambogia
Claim to Fame: Enhance weight loss 2-3 times that of diet and exercise alone, reduce belly fat, increase mood, increase lean muscle mass, ease cravings, support digestive function and inhibit production of cholesterol.
What is it? A green South-East-Asian fruit that turns yellow when ripe, traditionally used in Indian medicine or as a flavouring in food.
How it ‘works’? The active ingredient, hydroxycitric acid (HCA) is linked with appetite suppression by increased release or availability of serotonin from the brain. It is often combined with other ingredients like caffeine or green coffee bean extract.
Reality check: A systematic review and meta-analysis found only a small overall effect of 1% difference (0.88kg) in body weight lost between those taking HCA and those on placebo. All 12 randomised controlled trials included had methodological weaknesses and all but two included dietary interventions reducing intake between 4200-12600kJ. Jump across to my blog Dietitian without Borders and read more about Garcinia Cambogia Miracle weight loss supplement?
Green Coffee Bean Extract
Claim to Fame: Encourages your body to use stored fat for energy, reduces sugar cravings, reduces glucose absorption and helps to reduce fatty storage deposits.
What is it? The green raw seeds inside red coffee berries that haven’t been roasted but instead are soaked and concentrated to create the extract.
How it ‘works’? Chlorogenic acid, the active ingredient thought to be responsible for weight loss in green coffee beans is reported to inhibit the release of glucose to melt fat off your body, starting at the liver.
Reality Check: A 2012 randomized placebo-controlled study with 16 participants found an average weight loss of 1.5kg or 2.0kg when taking 700mg or 1050mg green coffee bean extract over a 6 week period (0.25-0.3kg loss/week). No dietary changes were made and the placebo group showed no change in weight. While the results are promising, longer studies with more participants and strong methodological quality are needed according to this systematic review. Our colleague Janet Helm RD from Nutrition Unplugged has more to say on why Green Coffee Bean Claims are hard to swallow.
Green Tea Extract
Claim to Fame: Decreasing high levels of fat like triglycerides and cholesterol in the blood, enhance metabolism and may burn fat to aid with weight loss.
What is it? An extract obtained from dried, non-fermented leaves from the Camellia sinensis plant. Compounds called catechins which are thought to be responsible for the slimming effects. Manufacturers claim that each capsule of green tea extract can contain the equivalent of 8-9 cups of green tea.
How it ‘works’? Epigallocatecin gallate (EGCG) is the most abundant catechin. It is thought to either increase energy metabolism and fatty acid oxidation, reduce fat absorption or increase fat excretion, the specific mechanism of which is not yet known.
Reality Check: A Cochrane systematic review in 2012 found green tea extract to induce a small but clinically insignificant amount of weight loss in obese and overweight adults from randomised controlled trials of over 12 weeks duration. Studies showing an effect have been of short duration with few participants or used multiple ingredients. Professor Tim Crowe from Thinking Nutrition explains why Green Tea is more hype than substance.
Raspberry Ketone
Claim to fame: A miracle in a bottle for weight loss, it is claimed to help you lose weight, burn fat, boost your metabolism, increase energy levels and fight fatigue.
What is it? An aromatic compound found naturally in red raspberries. It’s low in abundance so you’d have to eat about 40kg of raspberries to get 100mg of ketone!
How it ‘works’? It reportedly increases production of the protein adiponectin to regulate metabolism, as well as directly breaking down fat stores.
Reality check: Only ONE study has involved humans using a supplement that contained 7 ingredients including raspberry ketone, ginger, caffeine and cayenne. It found that you could lose about 0.25kg a week if you also cut back by 2100kcJ AND did boot camp for an hour 3 times a week! I’ve written more about the human research on Raspberry Ketone for Weight loss on my blog Dietitian Without Borders.
Sea Kelp
Claim to Fame: Appetite suppressant and metabolism regulator.
What is it? A seaweed that grows in shallow and nutrient-rich waters around the world.
How it ‘works’? Sea kelp tablets contain iodine to help with thyroid hormone production and regulate metabolism. Fibres within sea kelp called alginates have been reported to significantly aid fat digestion and absorption.
Reality Check: A recent randomized controlled trial found that when combined with a energy-restricted diet, those taking alginate supplements on average lost 1.7kg more than those taking the placebo over a 12 week period (0.15kg per week). Another RCT found little benefit beyond a low-energy diet. Sea kelp tablets can contain anything from 150-360mcg of iodine – almost double the Australian RDI of 150mcg Iodine per day for adults. Excessive intakes can damage the thyroid and should be taken with care with supervision of a GP. Read more about the potential health benefits of seaweed and seaweed extract here.
Editor’s comment:
Thanks so much Gemma! It’s been wonderful getting to know you and your fanatastic blog all the way from the UK. I think it’s also important to point out the dangers of over supplementing, like this article you found for our facebook page on the spike in liver damage reported in the USA from dietary supps. And I don’t think that our lovely readers need me to point out I’m all about food, first. What say you?
