|Image 1: Losing consciousness is very different from losing body fat and while the former may require "burning" more than 800kcal, the latter does not.|
What's good for your obese neighbor...
... must not be good for you! I know, I am repeating myself here, but in view of the fact that my voice obviously has not been heard in Iran, as of yet, I will repeat my novel mantra as often as it takes for people to get it into their stup... ah, I mean stubborn heads and stop sending healthy people into misery.
|Figure 1: This is what the study particpants in the Hesa Koushki study had to endure - a "exhaustion exercise session" on the treadmill (Hesar Koushki. 2012)|
|Figure 2: Serum leptin, insulin, blood glucose, cortisol and lactate levels of young healthy, but untrained men before and after exhaustive exercise session (Hesar Koushki. 2012)|
When much is not yet too much, more must not be better either!
"According to the findings of this study [...] exercise longer than 60 minutes with energy expenditure higher than 800 kcal can be recommended for the reduction of leptin concentration in non-athletes." (Hesar Koushki. 2012)If we use our brains, though, the take home message would be very different an should rather read like: "NEVER! Expend more than 800kcal in one workout if you are not leptin resistant and want to make sure that you don't forestall fat loss and mess up your endocrine system." (Dr. Andro ;-)
Fat loss training for non-obese individuals should focus on keeping leptin levels steady!
Once you acknowledge the importance of normal leptin levels for fat loss and overall metabolic health in lean, not leptin resistant individuals, the same review (Bouassida. 2010) the Iranian scientists cite to support their (misleading!) conclusion that it would be basically nonsensical to do intense short bouts of exercise, since those do not reduce circulating leptin levels has to be interpreted in a completely different way.
Just as the complete failure to produce insulin would not just hamper your gains, but have you literally shrivel away, lowering leptin levels in an already lean, if not very lean individual even further will sooner or later whack your metabolism and endocrine system (infertility, low testosterone, amenorrhea, you name it...). Not to mention that you will obviously not be able to derive any of the metabolic benefits of adequate leptin levels and receptor activity (figure 3).
So what can or must be done to keep healthy leptin levels and sensitivity?
Lean, athletic individuals should thus focus on shorter (below 1h), intense and glycolytic workouts (HIIT, lifting weights) and regenerative 'cardio' work in the << 800kcal energy expenditure range and make sure that they...
- get enough sleep - even a moderate sleep debt will increase the production and systemic circulation of TNF-alpha and IL-6 and reduce the expression of adiponectin and leptin in the adipose tissue (Padilha. 2011)
- strategically cycle & refeed on carbohydrates - it stands out of question that a reduction in carbohydrate intake is an effective means to get rid of body fat, but it will work optimally only, if you strategically cycle (higher carb intake on workout, lower carb intake on non-workout days) your carbohydrate intake, integrate regular refeeds (with a 20% caloric deficit every other week) and always eat as much green leafy veggies as it takes to fill you up without ever counting their quasi non-existent carbohydrate content
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