Friday, November 28, 2014

Calorie Shifting (Refeeding) for Max. Fat Loss: Classic Body Building Principle Has Overweight Women Lose 8kg of Pure Fat in 42 Days - 2.6x More Than Calories In vs. Out Predicts

Want to lose that blubber in a minimal amount of time? Diet like a bodybuilder and don't forget to refeed, Ladies!
Calorie shifting? What's that? Don't worry. I have been asking myself the same question, when I first read the title of a recent paper from the Shaheed Beheshti University of Medical Sciences and Health Services and as it turned out, I was well aware of the principle, but didn't know scientists would call the classic diet - refeed cycles bodybuilders have been using for ages "calorie shifting".

The principle is as simple as effective. You're dieting for 11 days and "refeeding", i.e. eat ad-libitum for three days. The intention is to achieve a temporary deficit that's large enough to induce significant weight and fat loss in spite of the potential of temporary over-indulgence on the refeeding days.
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Common sense and years of practical experience inform us that this way of dieting works, but scientific evidence is yet scarce. The latter obviously cannot be said of the beneficial effects of using moderate amounts of caffeine on a diet to (a) increase the oxidation of fatty acids and (b) stabilize your energy levels. Against that background it appears smart that thirty of the sixty overweight or obese, but otherwise healthy women (aged between 26- 45 y) with sedentary life styles, who were selected to participate in the study at hand followed a calorie shifted diet (CSD) and supplemented with 5mg/kg of caffeine on both the calorie reduced and the ad-libitum days of their diet.
Figure 1: Overview of the three 4-week phases of the study and the respective energy intake.
As you can see in Figure 1 there was a hardcore dieting phase (phase 1 + 2 | day 1-14 + 15-28), in the course of which the subjects consumed ~800kcal less than on their regular diets and a 4-week normalization phase (phase 3 | day 29-42).
"All subjects were instructed to consume their meals (containing determined calorie) only at 4 set of meals every day and avoid any other intake at other times of day. The time for each of these meals was optional and they were free to consume in any hour, but the time interval between meals could not be less than 4 hours (e.g. 8-12-4-8)." (Davoodi. 2014a)
The subjects had to follow their 55% carbohydrate, 25% protein, 20% fat diets "to the T" for the previously mentioned 11 dieting days which were followed by 3 days of self-selecting food and energy intake. The 11-3 day-cycles were repeated 3 times (for 42 days) and followed by a whole follow-up period, in the course of which subjects received a diet containing 55% carbohydrates, 20% protein and 25% fat that was designed to match their individual energy requirements.
Calorie shifting beats the crap out of regular dieting by preserving the dieters' RMR (Davoodi. 2014b)
Is calorie shifting superior to regular calorie restriction? Yes, it does! As I've pointed out in the introduction, there are only few studies investigating the effects of diet / refeeding cycles, but a previous study by the authors of the study at hand (Davoodi. 2014b) shows overweight women lose significantly more body fat on a calorie shifting vs. regular diet; and, more importantly, kept the fat off during the weight maintenance phase - probably due to the conservation of their resting metabolic rate, which goes hand in hand with slightly reduced hunger scores and a higher rate of satisfaction with the diet.
The study design is not too difficult to understand, right? A significant reduction in calorie intake for 11 days that should suffice to strip 3.1kg of pure fat off the overweight physique of the study participants (assuming that you need a deficit of 7,000kcal to lose 1kg of body fat) if they didn't overeat on the ad-libitum days.
Figure 2: Body weight and body fat levels in % of baseline (Davoodi. 2014a)
And surprise! In this case the "optimistic" calories in vs. calories out calculation is actually not optimistic enough. Instead of the calculated 3.1kg of body fat, the ladies lost 8.04 kg of pure fat! That's 2.6x more fat than you would predict based on the stupid in vs. out calculation!

There is yet another surprise: Caffeine does not promote fat loss!

Yes, you read me right. Take another look at the data in Figure 2. While the weight in the caffeine group dropped faster, the weight / body fat loss in the group who abstained from caffeine was significantly more favorable.
Figure 3: Ratio of fat to weight loss - higher values = more favorable changes in body composition.
While the extreme difference in the first week could still be an outlier, there is a non-negligible trend towards more favorable changes in body composition in the "non-caffeinated" dieters (see Figure 3).

It is important, thought, to point out that this advantage occurred only during the active weight loss study. During the one-month follow up the addition of caffeine during the dieting phase inhibited the minor body fat rebound of 0.78kg and may - according to Davoodi - be what triggered the additional 1.54kg body fat loss, they observed during the maintenance follow up (Davoodi. 2014b)
Figure 4: If the fat loss alone was not impressive enough for you, what about the absence of a fat rebound?
Bottom line: While the caffeine-disadvantage comes as a surprise and is difficult to explain (could be an increase in cortisol that blunts fat loss, specifically in the obese) the overall message of the study at hand is clear: the good old bodybuilding diet / refeed regimen works and it works extremely well in overweight and obese women...

I mean: Can you remember another study, where the subjects lost almost 30% of their body fat and did not experience a weight rebound (in the caffeine arm, they even kept losing fat, see Figure 4) after a 42 day weight loss intervention? I can't and I have read my share of scientific papers | Comment on Facebook!
References:
  • Davoodi, Sayyed Hossein, et al. "Caffeine Treatment Prevented from Weight Regain after Calorie Shifting Diet Induced Weight Loss." Iranian Journal of Pharmaceutical Research 13.2 (2014a): 707-718.
  • Davoodi, Sayed Hossein, et al. "Calorie Shifting Diet Versus Calorie Restriction Diet: A Comparative Clinical Trial Study." International journal of preventive medicine 5.4 (2014b): 447.