|Image 1: If a high fat diet was a patentable pill, I guess BigPharma would already be selling it.|
- The healthy and lean (and not anorexic) will pass by without even noticing the great "0.00001% fat, reduced sugar whatever" with the Weight Watchers sticker on it.
- The hungry-looking slightly overweight to morbidly obese people will pick up the aforementioned "0.00001% fat, reduced sugar whatever" with the Weight Watchers sticker on it, look at the price-tag, sigh and put three packets of that stuff into their cart.
Please understand: Low carb = high fat! And high fat burns, not stores fat.
I guess, I better stop preaching now and get to the nitty gritty of the latest study on the effects of a high fat vs. low fat diet on short-term (2-days) metabolic adaptations in lean (BMI 19-25kg/m²) and obese (BMI 30-40kg/m²) human subjects.
|Figure 1: Relative energy content of the low and high fat diets the lean and obese study participants were fed (data adapted from Bergouignon. 2012)|
|Figure 2: Total 24h kcal expenditure (left axis) and protein, carbohydrate and fat oxidation (right axes) in lean and obese subjects on the low and high fat diets (data adapted from Bergouignon. 2012)|
|Figure 3: Free fatty acid and triglyceride levels (24h AUC in mmol/dl and mg/dl, right axis) and free fatty acid to triglyceride ratio (left axis; data calculated based on Bergouignon. 2012)|
|Figure 3: Total mRNA expression in vastus lateralis muscle of study participants expressed relative to the subjects in the lean low fat group; please note the discontinuity of the axis between 200% and 600%, which became necessary to fit the data into the graph (data calculated based on Bergouignon. 2012)|
Is a high fat diet exercise in a pill? ...
If we discard the statistical shenanigan for a moment, you may yet notice the "non-significant" +33% increase in Sirtuin 1 (Sirt 1) expression in both high fat diet groups. The intelligent and well-read SuppVersity student you are, you will also remember that this protein, which is downregulated in states of insulin resistance, has been identified as one of the key players in the anti-cancer effects of compounds such as resveratrol and the longevity effects that have been ascribed to low-calorie diets. And as if that was not enough, Sirt 1 also plays a key role in the beneficial adaptations that come with exercise, where it is part of a triumvirate of AMPK + SIRT1 + PGC1-alpha, which is induces the production of irisin the purported "exercise hormone" that is supposed to "brown your adipose tissue" (meaning to convert the sluggish white into the metabolically more active brown fat) has gotten quite some attention in the lay press as of late (eg. LA Times).
|Figure 4: Skeletal muscle mRNA expression (in au) of acetylated (=inactive) PGC1-alpha and phosphorylated (=active) AMPK in lean and obese subjects subjects on low and high fat diets (data adapted from Bergouignon. 2012)|
... it sure looks like that!
In combination with the increase in phosphorylated AMPK (p-AMPK, click here to learn more about the "mTOR/AMPK Seesaw"), which was likewise statistically significant, the short-term adaptation to high fat feeding in lean and obese human beings shares two of the main characteristics of the "healthy endurance training" the same Dr's who warn their patients about the dangers of a high fat diet usually prescribe to their patients. Now tell me, is the voice in your stomach still telling you that low-carb may be good, but that eating a high fat diet is not an option? Well, in that case I guess you are beyond help... go buy some low-fat sugar reduced cornflakes ;-)