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Commonwealth Champion Powerlifter – @DomCadden
The claims about the super-ingredients in ‘fat burner’ supplements sound too good to be true – and they often are! Here we chew the fat on some of these ingredients, with thanks to the findings of an Obesity Reviews journal meta-analysis of “nutrition supplements that increase fat metabolism”.
The effects of caffeine on fat oxidation (“burning”) are relatively small, but they are well established. Caffeine has been proven to produce short-term thermogenic effects (i.e. burn more calories at rest) even at low doses (100mg – a weak cup of instant coffee), although a high dose (8mg per kg – a double or triple espresso) can significantly increase the rate of calorie burning at rest in the three hours after you have it, as long as you’re not a habitual high-caffeine consumer. Caffeine also stimulates the sympathetic nervous system to help free up fatty acids for oxidation (“burning”). This works well during low-intensity exercise, but the effects are less obvious during moderate or high-intensity exercise.
The caffeine in foods is bound in compounds that change how it acts. For example, coffee reaches peak strength about 30-90 minutes after ingestion, guarana takes longer to reach peak effectiveness (how long depends on its form) and last longer, whereas caffeine anhydrous (found in pills and supplements) kicks in more instantly.
Green tea is a well-researched substance that contains compounds known as catechins. One of these, epigallocatechin gallate (EGCG), can inhibit an enzyme that breaks down norepinephrine, the neurotransmitter involved in regulating metabolic rate and fat-burning. This action keeps metabolism and fat-burning elevated for longer, especially when coupled with additional caffeine to free up fat from fat cells.
Obesity Reviews notes that green tea’s effect on fat oxidation works both at rest and during exercise on fat loss, but these effects are “relatively small”. For best results, the ECGC concentration should be high – in an extract, rather than drinking a standard green tea.
L-carnitine is found in red meats and dairy, but it’s also produced in the body – in fact, even when dietary carnitine is considered ‘insufficient, healthy people synthesize enough carnitine in the liver and kidneys to survive.
It’s true that L-carnitine plays an important role in fat metabiolism, especially in a fasted state when you’re doing low to moderate intensity exercise. Supplementing with L-carnitine is based on the assumption that this will increase muscle carnitine concentration and therefore increase fat oxidation. Carefully conducted studies have proven that eating extra carnitine does not produce greater muscle carnitine concentration, so Obesity Reviews claims that eating carnitine promotes fat loss are “not only unfounded, but theoretically impossible”.
According to the Handbook of Obesity: Clinical Applications, research studies on rats suggested that the amino acid L-tyrosine may enhance a sense of wellbeing when calories are cut back. (What indicates “enhanced wellbeing” in a rat? Rosier cheeks? Not eating their own faeces?) Since L-tyrosine helps your brain’s ability to create neurotransmitters such as dopamine, it’s thought you will seek to use food less to create dopamine. Based on this, it is believed L-tyrosine may suppress appetite.
L-tyrosine is often claimed to help you lose weight by boosting metabolism, but the University of Maryland Medical Center and others have stated that there’s no proof to support this. Another claim is that it works well when “stacked” with products containing caffeine, ephedrine or phenylpropanolamine. Well, ephedrine is banned in Australia, phenylpropanolamine has been pulled from sale even in the USA and caffeine is a proven fat burner, so that’s probably what’s doing the work.
CLA has had positive results on fat loss in mice, but results in humans have been inconsistent. Supplementation with CLA has been shown to reduce food intake and an increase in calorie burning. Obesity reviews concluded that “modest fat loss” may be achieved by long-term supplementation if you have a lot – about 3g per day. However, there is concern over safety and one study found a three-month daily supplementation with CLA significantly lowered insulin sensitivity (15%) in overweight Caucasian men.
Taurine, one of the magic ingredients in energy drinks, is an amino acid. Obesity Reviews looked at some studies they felt were flawed or insubstantial and declared that there was “insufficient evidence that taurine has a stimulating effect on fat metabolism”.
We get taurine from protein-rich food foods such as meat and fish, but there have been warnings against having more than 3000mg a day. There’s concern that scientists know little about how taurine affects your body in the long term.
In Amino Acids and Proteins for the Athlete, author Mauro Di Pasquale claims that taurine can keep you from losing muscle mass during periods of rapid weight loss as it increases your body’s sensitivity to insulin and boosts your protein synthesis – two factors that aid in muscle development. This is based on one study on mice, another on 30 Japanese students who lost weight and body fat with taurine supplementation.
The fruits of the garcinia family are often used to make hydroxycitric acid (HCA), which is the hot new thing weight-loss supplements. However, HCA from garcinia can affect your body’s sugar metabolism, which is why diabetics are often warned off it.
HCA appears to block your body’s metabolism of simple sugars into fats. It is also claimed to suppress appetite by increasing serotonin levels and stimulate the burning of stored fat for energy during long-duration exercise. There is very little scientific evidence to support this.
It’s often pointed out that mangosteen has been used medicinally in Southeast Asia for centuries, which of course is supposed to make us feel all warm and fuzzy. But it has been used as a tea for conditions such as diarrhea, bladder infections and gonorrhoea. Not weight loss.
It might be incorrect to call fibre supplements “fat burners” but they are a surefire way to suppress hunger, give a feeling that you’re satisfied with smaller portions and reduce absorption of the other food you eat. All this makes them an easy and safe way to achieve the modest calorie deficit (ingesting less calories than you burn) that will lead to fat loss. It really is that simple.
It would be great if even half the things you read and hear about fat loss supplements are true, but the vast bulk of these claims come from sources that make, sell or advertise supplements or they are funded by these companies. Too often these claims cling to tiny or old studies that may or may not have involve humans or they twist one aspect of a study or the chemistry to suit their sales pitch. Unfortunately, fat loss mostly comes down to diet and exercise.