You won't lose weight by popping pills
Supplements can be tempting if you're looking for a quick fix, but most have little or no scientific evidence to support their claims
LESLIE BECK
Globe and Mail
January 21, 2009
globeandmail.com: You won't lose weight by popping pills
As a registered dietitian in private practice, I'm often asked to recommend a supplement that speeds up weight loss. It's hard to ignore the rows of fat burners, metabolism boosters and appetite suppressants on store shelves - and the hundreds of products hawked online - all promising a fast track to weight loss.
It's an appeal that's hard to pass up if you're impatient for results. If you're looking for a magic bullet that's less demanding than cutting calories and increasing exercise, weight-loss supplements can be tempting.
But do diet pills really help you shed pounds? Or do they just slim down your wallet?
Despite the claims, most products don't work. While some supplements may give you a small advantage in the battle of the bulge (if you also eat less and work out), most have little or no scientific evidence to support their claims.
In fact, in January, 2007, the U.S. Federal Trade Commission received a $25-million settlement from the makers of four prominent weight-loss supplements - Xenadrine EFX, CortiSlim, TrimSpa and One-A-Day Weight Smart - for false advertising. Like many products, these supplements made claims of effectiveness without supporting research.
What's more, some supplements have side effects that can be downright dangerous.
Many weight-loss products combine a cocktail of ingredients such as herbs, plant extracts, caffeine, vitamins and minerals. Others are made from a single ingredient touted to suppress appetite or block calorie absorption.
If you're considering adding a supplement to your 2009 weight-loss plan, here's what you should know about popular products.
FAT BURNERS
Also called "thermogenic" supplements, these products are purported to increase metabolism (the rate at which the body burns calories) and speed fat breakdown. Fat-burning ingredients added to weight-loss supplements include bitter orange (citrus aurantium or Advantra Z), green tea, CLA (conjugated linoleic acid) and hydroxycitric acid (garcinia cambogia).
You will find them in products called MetaSlim (green tea), Swiss Daily Lean Fat Burner (CLA), GNC Cuts (green tea), Extreme Burn (Citrimax), and One-A-Day Weight Smart (green tea). (Despite its name, the company's website states that One-A-Day Weight Smart is not a weight-loss product.)
Supplements containing bitter orange, a stimulant, should be avoided. The evidence that it works is conflicting (there are only two published studies) and bitter orange has been linked to reports of stroke and heart problems in healthy people who took it alone or in combination with other stimulants such as caffeine.
Don't waste your money on supplements made from hydroxycitric acid either. Among the three published studies, not one found the supplement reduced weight, increased fat burning or boosted energy expenditure in obese people.
Despite the flood of green tea supplements on store shelves, the evidence is sparse that it can melt the pounds away. In one study, green tea increased fat burning and metabolism in 10 healthy men who were lean or mildly overweight. But the study was not designed to assess weight loss.
Preliminary research did suggest that a specific green tea extract could help reduce weight in overweight people. However, recent studies concluded that taking a green tea extract does nothing to reduce body weight or maintain weight loss.
Although it's not conclusive, there is some evidence to support the fat-loss claims of CLA, a supplement made from a fatty acid found in meat and dairy products. Taking 0.7 to 4.5 grams of CLA a day has been found to significantly reduce body fat and increase muscle mass in some people. (However, the supplement doesn't appear to reduce body weight or body mass index.)
In one study, CLA supplements also increased feelings of fullness, but this effect didn't lead to reduced food intake or improved weight-loss maintenance.
There is also concern about CLA's long-term safety. Some studies have found increased insulin levels and insulin resistance - risk factors for Type 2 diabetes - in people with abdominal obesity taking a specific isomer of CLA. (An isomer is a compound that has an identical molecular formula to another molecule but a different structure.)
Most CLA supplements contain a mixture of CLA isomers; it's unknown whether these mixed products harbour the same risk.
APPETITE SUPPRESSANTS
These act on the central nervous system to decrease appetite or cause a feeling of fullness. A popular supplement in this category is hoodia (hoodia gordonii) derived from an African cactus. You will find hoodia in supplements called TrimPhase, Slimage and SlimQuick.
The active ingredient is thought to be a compound called P57 that suppresses hunger signals from the brain. But buyer beware: News reports suggest that some hoodia products sold on the Internet show no evidence of containing hoodia.
Despite the hype, it's too early to tell if taking hoodia will contribute to long-term weight loss. One unpublished study that was presented at a conference found that among obese men, hoodia users ended up eating about 1,000 fewer calories a day than those who didn't take the supplement. That's all there is to go on.
Weight-loss supplements containing fibre may also reduce hunger and cravings. PGX Daily (Natural Factors) contains a blend of fibres that expands in the stomach and intestines. Preliminary evidence suggests that taking PGX Daily two to three times a day reduces food intake and body weight. But study participants also dieted and exercised.
OTHER PRODUCTS
Other supplements marketed for weight loss include chromium (it may reduce body fat but it's unlikely to cause weight loss), apple cider vinegar (no published studies to assess its effectiveness) and starch blockers (murky evidence at best).
The bottom line: The most effective way to lose weight is the old-fashioned way - by making sustainable changes to your eating and exercise habits. Even if a weight-loss supplement did help you take off a few pounds, you would have to continue taking them to keep the weight off. And that may not be practical - or safe.
Leslie Beck, a Toronto-based dietitian at the Medcan Clinic, is on CTV's Canada AM every Wednesday. Her website is Leslie Beck, RD.
Supplements can be tempting if you're looking for a quick fix, but most have little or no scientific evidence to support their claims
LESLIE BECK
Globe and Mail
January 21, 2009
globeandmail.com: You won't lose weight by popping pills
As a registered dietitian in private practice, I'm often asked to recommend a supplement that speeds up weight loss. It's hard to ignore the rows of fat burners, metabolism boosters and appetite suppressants on store shelves - and the hundreds of products hawked online - all promising a fast track to weight loss.
It's an appeal that's hard to pass up if you're impatient for results. If you're looking for a magic bullet that's less demanding than cutting calories and increasing exercise, weight-loss supplements can be tempting.
But do diet pills really help you shed pounds? Or do they just slim down your wallet?
Despite the claims, most products don't work. While some supplements may give you a small advantage in the battle of the bulge (if you also eat less and work out), most have little or no scientific evidence to support their claims.
In fact, in January, 2007, the U.S. Federal Trade Commission received a $25-million settlement from the makers of four prominent weight-loss supplements - Xenadrine EFX, CortiSlim, TrimSpa and One-A-Day Weight Smart - for false advertising. Like many products, these supplements made claims of effectiveness without supporting research.
What's more, some supplements have side effects that can be downright dangerous.
Many weight-loss products combine a cocktail of ingredients such as herbs, plant extracts, caffeine, vitamins and minerals. Others are made from a single ingredient touted to suppress appetite or block calorie absorption.
If you're considering adding a supplement to your 2009 weight-loss plan, here's what you should know about popular products.
FAT BURNERS
Also called "thermogenic" supplements, these products are purported to increase metabolism (the rate at which the body burns calories) and speed fat breakdown. Fat-burning ingredients added to weight-loss supplements include bitter orange (citrus aurantium or Advantra Z), green tea, CLA (conjugated linoleic acid) and hydroxycitric acid (garcinia cambogia).
You will find them in products called MetaSlim (green tea), Swiss Daily Lean Fat Burner (CLA), GNC Cuts (green tea), Extreme Burn (Citrimax), and One-A-Day Weight Smart (green tea). (Despite its name, the company's website states that One-A-Day Weight Smart is not a weight-loss product.)
Supplements containing bitter orange, a stimulant, should be avoided. The evidence that it works is conflicting (there are only two published studies) and bitter orange has been linked to reports of stroke and heart problems in healthy people who took it alone or in combination with other stimulants such as caffeine.
Don't waste your money on supplements made from hydroxycitric acid either. Among the three published studies, not one found the supplement reduced weight, increased fat burning or boosted energy expenditure in obese people.
Despite the flood of green tea supplements on store shelves, the evidence is sparse that it can melt the pounds away. In one study, green tea increased fat burning and metabolism in 10 healthy men who were lean or mildly overweight. But the study was not designed to assess weight loss.
Preliminary research did suggest that a specific green tea extract could help reduce weight in overweight people. However, recent studies concluded that taking a green tea extract does nothing to reduce body weight or maintain weight loss.
Although it's not conclusive, there is some evidence to support the fat-loss claims of CLA, a supplement made from a fatty acid found in meat and dairy products. Taking 0.7 to 4.5 grams of CLA a day has been found to significantly reduce body fat and increase muscle mass in some people. (However, the supplement doesn't appear to reduce body weight or body mass index.)
In one study, CLA supplements also increased feelings of fullness, but this effect didn't lead to reduced food intake or improved weight-loss maintenance.
There is also concern about CLA's long-term safety. Some studies have found increased insulin levels and insulin resistance - risk factors for Type 2 diabetes - in people with abdominal obesity taking a specific isomer of CLA. (An isomer is a compound that has an identical molecular formula to another molecule but a different structure.)
Most CLA supplements contain a mixture of CLA isomers; it's unknown whether these mixed products harbour the same risk.
APPETITE SUPPRESSANTS
These act on the central nervous system to decrease appetite or cause a feeling of fullness. A popular supplement in this category is hoodia (hoodia gordonii) derived from an African cactus. You will find hoodia in supplements called TrimPhase, Slimage and SlimQuick.
The active ingredient is thought to be a compound called P57 that suppresses hunger signals from the brain. But buyer beware: News reports suggest that some hoodia products sold on the Internet show no evidence of containing hoodia.
Despite the hype, it's too early to tell if taking hoodia will contribute to long-term weight loss. One unpublished study that was presented at a conference found that among obese men, hoodia users ended up eating about 1,000 fewer calories a day than those who didn't take the supplement. That's all there is to go on.
Weight-loss supplements containing fibre may also reduce hunger and cravings. PGX Daily (Natural Factors) contains a blend of fibres that expands in the stomach and intestines. Preliminary evidence suggests that taking PGX Daily two to three times a day reduces food intake and body weight. But study participants also dieted and exercised.
OTHER PRODUCTS
Other supplements marketed for weight loss include chromium (it may reduce body fat but it's unlikely to cause weight loss), apple cider vinegar (no published studies to assess its effectiveness) and starch blockers (murky evidence at best).
The bottom line: The most effective way to lose weight is the old-fashioned way - by making sustainable changes to your eating and exercise habits. Even if a weight-loss supplement did help you take off a few pounds, you would have to continue taking them to keep the weight off. And that may not be practical - or safe.
Leslie Beck, a Toronto-based dietitian at the Medcan Clinic, is on CTV's Canada AM every Wednesday. Her website is Leslie Beck, RD.
