Two weeks ago I decided to attempt the Rapid Fat Loss (RFL) diet as outlined by Lyle McDonald (which can be found
here). It is essentially a Protein Sparing Modified Fast, or PSMF. As the name implies, this means that it's essentially a fast, but protein sparing (so food intake is limited solely to protein and non-starchy vegetables). I won't go too much into the diet, but in short I spent 12 days eating roughly 300g of protein and vegetables, with negligible amounts of carbs and fats. I did include some carbs around my workouts, but they were minimal. My daily caloric intake was roughly 1300-1500 calories (resulting in a nearly 2000 daily caloric deficit for someone my size).
The handbook called for introducing up to 30g of carbs pre/intra workout, but I ended up raising that to at least 50g near the end. If I had to redo it I'd definitely bump up the carbs around workouts since they really don't contribute much to the overall intake (50g of carbs would only add 200 calories) and there's also the fact that you're probably going to burn at least that much during the workout itself. The only big detriment that I can foresee would be replenishing your muscle and liver glycogen stores too much (which will help you get a nice workout, but will temporarily slow the rate of fat loss until those stores can be depleted again).
Needless to say, it sucked. But it worked. Before reintroducing carbs, my total weight loss was about 17 pounds. After carbing back up, my total loss continues to be on the order of 11-13 pounds. I am visibly leaner (at least to my own eyes). My strength did take quite a hit, but what do you expect? 11-13 pounds of fat and muscle is enough to seriously change your leverages.
I wouldn't suggest this to anyone who doesn't have a lot of self-control and some experience dieting, because it's definitely the hardest short-term diet I've done. I was quite lethargic and running on reduced brain capacity for a little while there. This is NOT a long-term and sustainable dieting solution, but it is a nice way to do a quick body recomposition or as a kick start to a longer and more moderate diet. Please read the handbook if you're actually going to attempt it since you will put your health at risk if you don't. Lyle also suggests using an EC stack (ephedrine/caffeine) during the diet, which I did, but I had previous experience using those products and knew I had a high tolerance for stimulants. So, if you opt to do that, start low and assess your own tolerance.
I'd like to thank Greg Maller for showing me the diet and answering my questions throughout the process. He has done this diet multiple times and it was on his recommendation that I decided to do it.
If anyone has specific questions about it, you can email me at jbb242 (at) cornell (dot) edu.
