Probably the most common definition when used in every day conversation is the theory that when you stop eating for a certain period of time, your body will go into starvation mode and start to eat away at your lean mass (muscle, skin, organs, etc) in order to slow the metabolism down so that your body doesn't need as many calories to function, thus allowing you to live on a smaller amount of food.
The starvation mode theory even has it going so far as saying that you need to eat once every 3-4 hours in order for your body to avoid eating away at all the hard earned muscle you've been developing. I'll admit, this is what I learned a number of years ago, follow it to this day, and advise my clients to do so as well.
But, I found this study that tells a very different tale.
The study was actually looking at historical studies and comparing how starvation (or very low caloric diets) would affect the basal metabolic rate (BMR) between lean and obese individuals. In other words, in a controlled setting under controlled conditions, when individuals were fasting or on extremely low-calorie diets, what was the effect on their metabolism?
One of the first things that is mentioned I think is extremely fascinating:
...during the first 2 days of starvation there is often a small absolute increase in BMR relative to values obtained after an overnight fast.
After two days of starvation, they actually saw an INCREASE in people's metabolism.
Another quote:
As early as 1907, VAN NOORDEN wrote "during the first few days of acute starvation the general metabolism of the body suffers no diminution".
Again, "NO DIMINUTION" of the metabolism during the first few days of acute starvation.
The study also goes on to say that even protein oxidation tends to show an increase over the first few days of acute starvation.
It kind of throws a little curveball at the idea that we have to eat 6-7 meals a day, one every 3-4 hours in order for us to keep our metabolism going and to not fall into "starvation mode."
When thinking about this from an evolutionary standpoint (and I'm not basing this on anything other than what is popping up in my brain), this makes a lot of sense.
You're an early human 50,000 years ago. Food is always sparse and you never know when your next meal is going to come from. If the body was designed to start eating away at your lean mass immediately after not having food in it for a few hours (or even a few days), then you wouldn't have the energy and strength to take down that mammoth that's rolling through your neighborhood on a cross country tour. Humans (and if you think about it, any species for that matter) wouldn't be able to survive if we had to keep eating every few hours in order to keep our lean tissue intact in order to have the energy to continue to hunt for food.
Now going further into the study, it does show that after the initial 1-3 days of starvation, this increase in BMR and protein oxidation starts to decrease.
But overall, I think the take home point is, relax and don't worry so much about skipping a meal or thinking that if you don't eat every 3-4 hours your body is going to turn into the Blob and all your muscles will shrivel up into raisins. If you've got your overall eating under control and you're on an efficient resistance training program, you'll be just fine.
When Exercise Will Kill You
This was just such a bizarre story I had to include it in the blog.
www.leanbodyfitness.com
1 comment:
To this day, we are taught to fear starvation mode and slow metabolism, a state when the body clings on to fats. However, military research proves otherwise!
Starvation mode / slow metabolism - military says no fear
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