“CAVEMAN’S FASTING DIET MAY LEAVE WOMEN DIABETIC,” reads an article in the Daily Express on January 29, 2013.

This, of course, ties back to the 5:2 fasting fad, where dieters are told to severely restrict calories for 2 days a week, and then indulge in whatever they want on the other 5 days. In November 2012, The New Scientist Magazine raised some concerns about this diet, so perhaps it should come as no surprise that some are now reporting adverse effects of this latest fad. The New Scientist noted that the research behind the fasting diet was carried out on rats and mice, for which it worked well. BUT it didn’t work in primate research: humans, of course, are at the top of the primate tree. So, I suppose the question that could reasonably be posed to fans of the 5:2 fasting approach is “Are you a man or a mouse?”

The point made in the Express report is that while the diet appears to work for men, women are at potential risk of serious health problems, including diabetes. And it all comes down to one of the main tenets of my favorite nutritional approach: body composition! The article explains the dilemma as follows:

Men have a higher percentage of muscle, which gives them a faster metabolism than women. This is because muscle actively burns calories, while body fat is a store of calories. Therefore, if a man and woman of comparable size restrict their dietary intake to 800 calories per day, the man will inevitably lose more weight than the woman.

The fact that men generally have more muscle mass than women also seems to protect them from some of the diet’s downsides. This is explained as follows:

The average adult delivers 300 grams of protein a day. Eighty percent of that is recycled, broken down, and reused; a bit like Lego bricks. After a certain period of time, these proteins wear out, can no longer be used again in the body’s natural recycling processes, and are effectively lost from the body. What we cannot save, we need to replace. That replacement must come through the diet.

Protein is non-negotiable, and unlike other micronutrients, you need it every day. What this means is that the body has no way of storing excess amino acids, the building blocks of protein, so we essentially need to consume a variety of amino acids every day to provide the body with these essential “Lego bricks.” If amino acids are not available in the diet, then the body begins to sacrifice its own muscle to release the protein and amino acids needed for this recycling process.

Of course, once you start skipping meals, you will compromise your intake. Because men have a greater muscle reserve, they can draw on it for protein on fasting days. Women, however, soon begin to lose too much muscle and it adversely affects their body composition to a much greater degree than men.

Here we have it again: It’s just not true that you can eat whatever you want and lose weight in a healthy way. What we eat affects our body in many ways – we need nutrients based on our own unique body and lifestyle to make sure we eat everything we need to sustain, maintain, and repair our body. Any diet that doesn’t protect, or even promote, your body composition is simply flawed: It can lead to weight loss, but there’s a chance you’re sacrificing healthy lean tissue and holding on to body fat.

http://www.express.co.uk/posts/view/373665/Caveman-fasting-diet-may-leave-women-diabetic/.