Mark Gilbert

Mark Gilbert BSc (Nutrition)
Mark is an expert in sports nutrition and dietary supplements. He has over 20 years of experience working with the biggest names in the bodybuilding industry.


L-carnitine is supposed to burn fat inside the muscle, but my biochemistry teacher said that the stuff’s a total scam. Is this true?

L-carnitine is not a scam. It’s a fascinating amino acid for many reasons. It’s essential to mobilizing fat and can increase fat burning.

Q. Why should I be taking glutamine? Is it a good fat burner?

A. Dr. Dan Reardon and I have never been huge fans of the amino acid glutamine because it’s never actually been shown to outperform other amino acids or other

Q. With my next fitness competition only a few months away, I need an edge if I’m going to place. Should I buy organic foods to prepare my meals this time? Is going organic healthier?

A. Okay, I’ve been saying this for

Q. I drink diet cola when I’m cutting up because it has no calories. It feels almost like a cheat because it tastes sweet, but I’m a bit concerned. I keep hearing that sweeteners are unsafe. Do they really promote fat gain and cause calcium leaching from

Q. Mark, I read your column every issue for supplement advice. Why haven’t you started your own supplement company?

A. A few reasons, really. If you look at virtually everyone who’s ever started a highly successful

Q. How powerful is ephedrine as a fat burner? In your opinion, was the USA ban on its use justified?

A. Ephedrine is a stimulant similar to amphetamine but with substantially less potent effects. It was banned about five years ago in

Q. Is it true that whey protein can actually help you burn fat?

A. Last issue, I wrote about all of the underreported health benefits that make whey protein one of the healthiest foods you can eat, how it can increase nitric oxide, and the importance of

Q. What is beta–alanine and how does it work?

A. Beta-alanine is a non-essential, non-structural (it doesn’t get used to build proteins like muscle) amino acid. It increases the body’s carnosine levels. This allows the body to

Q. Mark, do the top pros actually use the supplements they endorse, or do they just use steroids? No bullshit, Gilly!

A. Anyone who’s been around a while in this industry knows plenty of guys use steroids. But virtually all of them also use

Q. I’m using a pre-workout powder and get unbelievable energy from the stuff. I read that it contains geranium in it, which is supposed to be responsible for the real kick you get. Have you used geranium, and, if so, what’s your take on it?

A. Recently,