Basal and Resting Metabolic Rate (BMR & RMR)

Posted on Posted in Diabetes, Diet, Fat burning, Food, Health, Healthy Habits, Insulin Resistance, Intermittent Fasting, Research, Weight Gain, Weight Loss

I think this would be a good time to introduce the concept of Basal Metabolic Rate (BMR), which is pretty much Resting Metabolic Rate (RMR), which most people know as your Metabolic rate. It is also known/related to your Basal/Resting Metabolic Expenditure per day.  I’ll treat all the definitions interchangably as they are all basically the same thing.

A more clear definition can be found here for the layman

https://www.acefitness.org/fitness-certifications/resource-center/exam-preparation-blog/616/bmr-versus-rmr

 

Basically, the rate of energy you burn in a day doing nothing.

In the above video from my favourite Doctor, Jason Fung, he talks about the Biggest Loser study 6 years on and what happens to their metabolic rate during the show and what happens to it 6 years afterwards.

The table below I got from the study’s website:

http://onlinelibrary.wiley.com/doi/10.1002/oby.21538/full

To sum it up, the contestants came in at a measure RMR of 2607 kcal/day.

After 30 weeks their RMR was measured at 1996 kcal/day

After 6 years thir RMR was measured at 1903 kcal/day.

Compare this to the predicted RMR of 2577/2272 and 2403 kcal/day.

Why is this?

Basically, the Biggest Loser is “eat less, move more” on “steriods” as Dr Fung puts it.

They still feed them, but just a whole lot less than they would normally eat, and then whip them with enormous amounts of exercise.

As calories in decreases, their RMR decreases.  They lose the weight because of all the exercise they do, and reduction in absolute calories coming in, but their RMR decreases to compensate for the decrease in calories.

As Dr Fung says, “obesity is a hormonal issue, not a caloric issue”, where he says “insulin resistance” is the key.  “Caloric reduction” is not the solution as your body goes into survival mode and reduces the amount of energy it uses per day because the input energy reduces.

So after 6 years, the contestants RMR is worse than when they started or at the end of the 30 week show (1903 vs 1996 and 2607), and they have gained back the weight.  They don’t do the ridiculous amounts of exercise they did on the show so the weight comes back, and their metabolic rate is 700 kcal/day worse than before.

The predicted RMR was based off the “eat less move more” philosophy to weight loss (which is wrong), and hence was way off.

Summary:

So what do I conclude from this set of results?  Watch the video, but I think:

  1. Consume the calories in the proper form and timing your body NEEDS to function healthily and properly
  2. Reducing your calories per day reduces your Metabolic rate which means you burn less when you do nothing.
  3. Intermittent Fasting/Fasting should be something that should be considered to control your insulin levels and weight control/loss.

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