It's not about the Calories

A recent study has provided further support that when it comes to regulating bodyweight the emphasis on 'Caloric content' is erroneous.

21 overweight/ obese individuals were recruited to participate in the study. To do so the subjects were required to demonstrate a loss of 10-15% bodyweight prior to the start of the study, as the purpose of the study was to investigate the ability to maintain weight loss, not create weight loss per se.

The subjects were divided into 3 groups; low fat; low glycemic; and very low carbohydrate. All diets were 'iso-caloric', meaning they contained the same amount of Calories, the difference being the macro-nutrient (Protein, Lipids and Carbohydrate) ratios that comprised the diets. The subjects followed these diets for 4 weeks.

The results were not really surprising; the low carbohydrate diet resulted in the least reduction in both Resting and Total Energy Expenditure, demonstrating a maintenance of metabolic rate. The low fat diet (similar to the usual dietary advice given by most health authorities) showed the largest drops in metabolic rate. The low glycemic diet was in-between these two diets, but closer to the low carbohydrate diet.

In a nutshell the difference in Total Energy Expenditure between the low fat Vs low carbohydrate is 300Kcal per day, even though the intakes were deemed similar.

There are flaws in the study, which hopefully a follow up study will resolve, but I expect the result will not be dissimilar.

So what is happening?

As I've said before, Calories are only vaguely related to how Humans process food. We don't consume Calories, store them or burn them, but because the term and idea has become so entrenched in the common psyche it's hard to get people to think using a different mental construct.

The study, in addition to Energy Expenditure, also measured a number of key hormones and this (the changes in hormones) begins to tell the real story.

The hormones measured (or related measures) were leptin, thyroid stimulating hormone, triiodothyronine, and free urinary cortisol, insulin sensitivity (indexes derived from an oral glucose tolerance test ), high-density lipoprotein [HDL] cholesterol, total cholesterol, triglycerides, plasminogen activator inhibitor 1 activity, and high sensitivity C-reactive protein [CRP].

For most indices the low fat group fared worst, whereas the low carbohydrate improved the indices most, except for two; 24 hour Cortisol excretion and C-Reactive Protein. Cortisol is a measure of stress and CRP is a measure of inflammation, both hormones are intimately linked with each other and also in adiposity via Insulin resistance, so this is a fly in the ointment of this particular dieting format.

The low glycemic group again was somewhere in the middle, showing improvements in most indices better than the low fat group, but not quite as good as the low carbohydrate group. However, the low glycemic group modulated their cortisol better (and probably as a consequence CRP), which is a known effect of low, but stable blood glucose/ Insulin.

So from a purely metabolic rate stand-point the low carbohydrate diet is the clear favourite, however, due to the Cortisol/ CRP issue, it's certainly not ideal.

The low glycemic diet demonstrated modulation of the Cortisol/ CRP pathways, but it didn't quite have the same metabolic impact of the low carbohydrate diet, so although good, again it's not ideal.

Is there a way to gain the benefits of all of the different diets? Absolutely. In fact we can actually surpass the benefits of any of the individual diets and utilise their specific strengths; it's all a matter of timing. Taking into account the temporal effect of physiology and adjusting our environment to account for this, we can hugely increase our metabolic rate and improve our biomarkers of health all without a need to deprive ourselves of any type of food.

If you'd like to learn how to do this, the Lean for Life Program will show you in the easiest possible manner. To find out more about this state of the art program, follow the link below. As a bonus, the Lean for Life Program is being offered at a 50% discount for the group beginning in August 2012.

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Reference:

Ebbeling, Cara B. Effects of Dietary Composition on Energy Expenditure During Weight-Loss Maintenance. JAMA. 2012;307(24):2627-2634. doi:10.1001/jama.2012.6607