Exploring the sense and nonsense of food and health

Four Popular Weight Loss Supplements – What’s the Evidence?

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As with most diet products, these are the newest ones to hype weight loss by taking the magic pill – if only it were true.  The only way to assess the effectiveness is by putting them to the test in a randomized clinical trial of sufficient size.  However, that usually is not the case.  Is there any evidence of this for these four products?  Read on.


The Web site sounds good and the testimonials are all positive – why wouldn’t they be?

The Claim: “Eat up to 30% less without feeling hungry” Clinically shown to work from the very first day.

Ingredients: Slim Shots contains natural oat, palm oil, artificial vanilla flavor, sweetener, aspartame (Phenylalanine) and beta carotene color.

Phenylalanine makes of 50% of aspartame, an artificial sweetener commonly used in diet products. ADD/ADHD patients and diabetics may experience negative side effects as a result of consuming this ingredient. Those with PKU, or at risk for PKU, should avoid Phenylalanine as it can cause brain damage or even death.

Evidence:  The website does offer some clinical studies.  In three of them, those people who consumed 2-5 grams of the product in the morning ate about 30% fewer calories at lunch and dinner than on the day they got a placebo.  In another study, consuming the product in the morning didn’t change how much women ate at lunch.  The studies didn’t last very long (only one day), so the results could not measure any weight loss effects.

There was on longer trial (18 weeks) did not measure weight in women.  Women who had lost weight (average of 17 pounds) regained only 3 pounds if they ate yogurt that contained 5 grams of the mixture two times a day.  This was compared with women who ate yogurt without the mixture who regained 7 pounds.

Long-term effects of consumption of a novel fat emulsion in relation to body-weight management

K Diepvens, S Soenen, J Steijns, M Arnold and M Westerterp-Plantenga

Int J Obes 31: 942-949; 2007

Objective: To assess weight maintenance after weight loss by consumption of yoghurt with a novel fat emulsion (Olibra) including effects on body composition, resting energy expenditure (REE), fat oxidation, hunger feelings and satiety hormones.

Design: A randomized, placebo-controlled, double-blind, parallel design. A 6-week weight loss period (2.1 MJ/day) was followed by 18 weeks weight maintenance with test (Olibra) or placebo yoghurt.

Subjects: Fifty overweight women (age: 18–58 years, body mass index (BMI) 25–32 kg/m2).

Measurements: In weeks 1, 7 and 25, a satiety test with questionnaires and blood samples for analysis of satiety hormones. In weeks 2, 8 and 26, REE, body weight and body composition.

Results: During weight maintenance after significant body weight reduction, there was no significant increase in body weight in the test group (1.13.4 kg); the placebo group did gain weight (3.03.1 kg, P<0.001). Compared to the placebo group, the test group was less hungry 4 h after yoghurt consumption in week 25 (P<0.05) and showed increased glucagon like peptide-1 values 180 min after yoghurt consumption (week 25 vs week 1, P<0.05). Measured REE as a function of fat-free mass (FFM) was significantly higher than predicted REE (P<0.05) in week 26 for the test group, but not for the placebo group. Fat mass (FM) was significantly more decreased in the test group (6.54.1 kg) compared to the placebo group (4.13.6 kg) (week 26 vs week 2, P<0.05).

Conclusion: Consumption of Olibra yoghurt improved weight maintenance compared to placebo, which can be explained by the relatively higher REE as a function of FFM, relatively higher decrease in FM and the relatively lower increase in hunger.

ACAI BERRIES AND JUICE (there are many supplements)

Claims: “Burn Fat”!  Lose Weight, Get Energized. Feel Great! “ Acai makes you eat less, metabolize fat faster, and lose weight.

Ingredients Acai (ah-SIGH-ee) berries

Evidence:  The Internet is bursting with Acai berry diets.  It was promoted by Oprah and from then has been touted as a “superfood”.

The berry comes from the acai palm tree in Central and South America and is a relative of the blueberry and cranberry.

All these darkly colored berries contain antioxidants called anthocyanins and flavonoids.  You have to consume the whole berry and most supplements contain only dried extracts.

All antioxidant foods are claimed to fight free radicals against heart disease and cancer and this may be true of the acai berry as well.  However, all these darkly colored berries offer this yet to be proven effect and so paying high prices for the acai berry products seems silly – instead have some blueberries for breakfast, have some cranberries, eat red grapes, and drink some red wine.

As far as the weight loss claims, the Federal Trade Commission says:

These diets are “utterly false with no evidence to support them”. The bottom line is don’t fall for false and fake testimonials, fake blogs, celebrity endorsements, and doctored before and after photos.


Claims: Lose 30 pounds without dieting!!!!  Eat all your favorite foods.

Sensa is intended to work with your sense of smell, fooling your  brain and stomach into thinking you’re full.  The term “sensory-specific satiety” is used to describe the process by which smell receptors send messages of fullness to your brain.

Ingredients:  Food flakes or crystals of maltodextrin, tricalcium phosphate, carmine, soy, and milk.  Savory flavors include cheddar cheese, onion, horseradish, ranch dressing, taco and parmesan cheese. Sweet flavors include cocoa, spearmint, banana-strawberry, raspberry, and mint.

Evidence: The company conducted two studies that have never been validated nor published in a peer-reviewed journal.  Based on the abstract of the larger study (found on the company’s website), Sensa was never compared with placebo crystals.  Four out of ten people never completed the study which suggests they were not experiencing any positive results.

Bottom Line: The hypothesis may be worth further testing to see if actual weight loss can be achieved or maintained by sniffing crystals, but until then don’t waste your $59 every month.

aLLI  (AL-eye).

Claim: “You can lose up to 50% more weight than you would from dieting alone”.  That means instead of losing 10 pounds, you would lose 15 pounds.  The claim is that weight loss is not effortless, but just easier with Alli.

Ingredients:  Alli is an over-the-counter diet pill.  It is actually one-half the strength of a prescription drug called Orlistat or Xenical).  It works by preventing about ¼ of the fat in foods from being absorbed, so the fat calories are lost in the stool.   There are side effects such as gas with an oily discharge and bowel incontinence.

Cost: The pills cost about $1.50 to 2.00 a day.

Weight Loss:  It seems to me that even though this drug has been well tested when it was a prescription drug, most of the results have been from the prescription dose rather that the lesser dose found in Alli.  (We discovered this from a graduate course presentation on the product).  Therefore, if the weight loss averaged about  6 pounds in obese women compared to the placebo group , what would the results have been at the lesser dose found in Alli?



One thought on “Four Popular Weight Loss Supplements – What’s the Evidence?

  1. Don’t just go about choosing any slimming pill that you come across just because it says that it’s natural. The best thing you can do is draw up a list of the diet pills that you think are suited for your purpose. Once that is done, conduct a thorough research on each one of them and only choose the one that is safe, actually contains natural ingredients, and has a history of efficiency.


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