This article is intended for woman audience. Your resting metabolic rate is determined by your internal organs and the rest of your lean body mass. If you do very little physical activity in a day, your resting metabolic rate will account for most of your calorie burn. If you do a significant amount of physical activity a day, for example one hour of exercise, then you can end up burning 20% more calories than your resting metabolic rate. Below is resting metabolic rate (RMR) for women gathered from several researches:
The data is presented in a range format and also there is one column on MEAN because its highly likely that your RMR will fall within the range and not exactly the same as the MEAN. Keep in mind that any extra calories your burn from a workout are not accounted for in above table. When you workout you'll be burning significantly more calories than what's the table indicates.
As you see on above resting metabolic rate table, there is a direct correlation between RMR and your height. Shorter people burn fewer calories than taller people. In research done by Amanda C., et al in 2010 here group directly measured the RMR of 47 women and compared it to the popular RMR estimator equations. The average RMR for this group of women was 1,027 calories per day.The average height of the group was 5'5".
Interestingly, the predictive equations all over estimated RMR, and the worst one over estimated by 700 calories. Its tough to hear it, but we all just need to eat fewer calories than we've been led to believe.
In a review of 11 studies done on resting metabolic rate in over 500 healthy adults both men and women, researchers found the highest average RMR to be approximately 1,800 calories per day i.e. the largest men and the lowest at 1,280 calories per day. This research included men and women of varying heights and groups of lean and obese individuals. The only correlation they found to metabolic rate was Fat Free Mass (FFM). FFM is all the parts of your body that are no fat, this includes internal organs, bones, and muscle mass. In other words your metabolic rate isn't affected by how much fat you have, it only matters how big or small you are underneath the fat, and that is largely determined by how tall are you.
Also, leaner people didn't have higher metabolic rates than the obese people. Further research done by Ravussin, et al in 1982 showed that the obese people actually had higher resting metabolic rates than the lean control group. The average metabolic rate of the obese people was measured at approximately 1,800 calories per day comapred to 1,450 calories per day for the normal weight control group. (The obese group was actually shorter on average than the controls so we sould guess based on height that their metabolic rate should have been lower if all other things were equal). The difference in metabolic rate was because the obese people actually had an average of 30 lbs more muscle; rather more of everything including organ mass, bone mass, and residual tissue mass (of which a small amount might have been muscle tissue). Out of all these tissues the most active ones that contribute the greatest proportion to your metabolic rate are your internal organs.
Research by Muller, et al, in 2011 shows that not only do your internal organs contribute the largest portion to your metabolic rate but that they scale to the height of your body and to the overall size of your body. In other words the taller you are and the bigger you are the bigger your internal organs are and thus the more calories they burn.
The following is a list of the relative amount of energy each tissue contributes to yoru daily metabolic rate per pound of each tissue (data from Bosy-Westphal, et al 2009);
- Heart: 200 cal / lbs
- Kidney: 200 cal / lbs
- Brain: 110 cal / lbs
- Liver: 90 cal / lbs
- Muscle: 6 cal / lbs
- Fat: 2 cal / lbs
- Bone: 1 cal / lbs
As you see from this data, your heart, kidneys, liver, and brain are the most highly metabolically active tissue in your body and as you will find out, they actually contribute the most to your metabolic rate. The amoutn of energy muscle uses at rest is actually much closer to the amount of energy fat takes. It really doesn't burn many calories when you're not working out.
Research by Heymsfield, et al. in 2001 indicates that approximately 69% of your resting metabolic rate is from your internal organs (specifically the combination of your heart, liver, kidneys, and brain). The other 31% comes from your bones, muscle, and fat tissue.
This research shows that striving to add extra muscle isn't going to increase your resting metabolic enough to change how many calories you can eat to lose weight and your metabolic rate is likely lower than you were lead to believe.
No comments:
Post a Comment