According to Mayo Clinic about 60% - 75% of the calories burned are non-exercise related. It seems each person's metabolism adjusts to ensure proper support of the body with the focus on efficient energy burn and seems to be geared towards burning less (back to our ancestors surviving on minimal food) as opposed to burning more. So, my question, how do we get our metabolism boosted and keep it elevated for those people looking to loose weight?
Basal Metabolic Rate (BMR), and it's sibling, Resting Metabolic Rate (RMR) refer to the amount of Calories your body will burn without any work done. They are similar, and for convenience sake most people are referring to RMR when they talk about daily Calorie requirements. Several things do affect those values, such as:
- Proportion of lean body weight to fat. Given two people at the same total body weight, the one with more lean mass will have a higher RMR.
- Total body weight. More cells in the body require more energy to service them. That's not a reason to go and binge, but given two people with the same body fat percentage, the one with a higher total weight will have a higher RMR.
- Thermic Effect of Food (TEF). Some foods require more energy to process than others. In terms of processing macro-nutrients: protein requires the most energy, carbs a distant second, and fat requires the least amount to process.
- Normal activity level. Someone with an active job like a construction worker will naturally burn more Calories than someone with a desk job.
So, the take-away from this is:
- Increase muscle mass. (note, a reduction in body fat is probably a good idea for other reasons)
- Eat a high protein diet.
- Be active a larger percent of the time.
Now, I have had training sessions where I burn up to 1400 Calories in the 90 minutes of training. Compared to my RMR of about 2400 Calories, that's 25% of the day's energy expenditure (2400 + 1400 - 150 [the 150 is correcting for the Calories I would have burned anyway] for the day). That fits in quite well with the Mayo clinic's report.
Also there are some advocates of intermittent fasting, such as Lean Gains, that put forth the body does a more efficient job burning Calories when you have a smaller number of larger meals. For example, if I ate 2400 Calories in 3 meals, each about 800 Calories, I would be more full and have a nice long time between the last meal of the day and the first meal of the next day.
One way is build more muscle. At rest, muscle burns more calories than fat.
When doing exercise, try and stay in the 60%-80% of max HR range. This is a fat burning range, and when you get beyond that you move into glycogen metabolism.
If you can get a higher Basal Metabolic Rate (BMR) by building more muscle, then sleeping burns more calories than before.
So lots of aerobic activity, at reasonable intensity should help.
Without a heart rate monitor there are two easy tricks to find 60% and 80%.
60% is easily identifiable as when you notice the sound of your breathing. Try, its pretty neat. Go for a jog, and at some point you start to hear your breathing, that is a good indicator you are at or over 60%.
80% is the point at which you will have a hard time talking to someone next to you.
Stay in that range, it builds muscles, builds aerobic fitness, and should help increase BMR.