Chapter 10; Body Composition and Physical Performance
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This is part 13 of my review in Layman's terms of the book 'The Art and Science of Low carbohydrate Living' By Jeff S. Volek, PhD, RD & Stephen D. Phinney, MD, PhD
this chapter is looking at the capacity for humans to adapt to a carb restricted lifestyle , which in turns allows the complete sparing of lean tissue and maintenance of physical performance. The aim is to loose excess body fat not the loss of muscle, hence scale weight is not the priority.
Why Body Composition is Important
Body composition is the body's relative proportions or content of fat mass and lean tissue. so ideally if weight loss is necessary the point is to maximize fat loss and minimize muscle loss. The reason for increased muscle is to contribute to metabolic health, this is more muscle equals greater tissue volume to take up blood glucose and more mitochondria that can burn fat! (In my 365 days of blogging and my alphabet headings when I get to M I will explain the mitochondria and how important it is for our energy).
Weight Loss and Body Composition
There are many variables in weight loss,including but not limited to,
level of calories and protein content
adequacy of mineral and vitamin intake
perhaps dietary carb intake
initial acitvity level
lean body mass content of each individual
type and amount of activity
net composition of the lost weight loss
Responses on body composition are impacted by change of diet, duration, quantity, quality, as well as the macro-nutrient make-up. This is why most studies done on diet (especially low carbohydrate diets) are to short which eventuates to a false negative result.
Dietary Macronutrient Distribution Affects Body Composition
With looking at 87 studies (published studies on weight loss) it was established that the diets that were low carb had greater fat loss. This weight loss was independent of exercise and energy intake.The diet that had better than the average intake of protein helped with prevention of loss of lean body mass. So its not about eating less its about the type and quantity of macro nutrients to help with weight loss.
Very Low Carbohydrate Diets and Body composition
In this section many studies are discussed, Volek showed that a hypo-caloric very low carb diet resulted in up to a 2-fold greater whole body fat loss than a low fat diet with a similar prescribed energy intake.. There is also proof of a reduction in insulin and leptin level in subjects that reduced carb intake, with even a small reduction in insulin levels helps with fat mobilization.
Importance of Resistance Training for Building Muscle
In the studies looked at here it was established that resistance training alone without caloric restriction of carbs does not necessary end up with weight loss. Where as resistance training in combination with carb restriction aids in the maintenance of lean body tissue.
Low Carbohydrate diets and Resistance training
a direct quote from this book "resistance training is a potent stimulus to increase muscle mass and strength, and thus there is good reason to consider weight training as an adjunct to a low carbohydrate diet for improving body composition and functional capacity". I should also mention that this is after adaption to a low carb diet, this is when your body is now using fat as fuel not carbohydrate anymore.
The studies that went passed 14 days with the subjects on a low carb diet observed no loss of peak aerobic power or peak muscle strength.
As said in this chapter as long as adequate intake of minerals is met along with adequate protein and fat intake a reduced carb diet is perfect for body mass and physical performance. This is as well as the tolerance of endurance and resistance exercise on a low carb diet.
this chapter relies a lot on studies , which is important in an evidence based situation. Also with the emphasis on making sure you are on a very low carb (keto) diet for up to 4 weeks before the body will become adapted to using the body fat for energy, this is very important. I have heard people talking that they have a low carb lifestyle and not loosing weight, they forget to mention they have a glass of wine with dinner (carb), a banana after a work out (carb), a slice of toast every now and again (carb). All these things will push you out of adaption, my advice is stay strict for at least 3 months , then use these things as a treat every now and again, but I guarantee you once you have done the 3 months you will no longer crave carb !