# Calories to Support Fat Tissue **URL:** \ **Category:** Factual Questions\ **Created:** [January 10, 2013, 5:07pm UTC](https://boards.straightdope.com/t/calories-to-support-fat-tissue/646765 "2013-01-10T17:07:24Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [January 10, 2013, 5:07pm UTC](https://boards.straightdope.com/t/calories-to-support-fat-tissue/646765/1 "2013-01-10T17:07:24Z")
Roughly speaking, how many calories per day does a pound of fat add to the typical person’s metabolic rate? I tried to search this on Google but I kept getting answers about the number of calories contained in the fat. That’s not what I’m asking about. TIA ---
**Author:** ![Darryl\_Lict](https://avatars.discourse-cdn.com/v4/letter/d/7cd45c/32.png) [@Darryl\_Lict](https://boards.straightdope.com/u/Darryl_Lict)\ **Post date:** [January 10, 2013, 6:07pm UTC](https://boards.straightdope.com/t/calories-to-support-fat-tissue/646765/2 "2013-01-10T18:07:30Z")
According to [Livestrong](http://www.livestrong.com/article/316732-how-many-calories-does-adipose-tissue-burn-per-day/), 2 calories per pound per day. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [January 10, 2013, 6:39pm UTC](https://boards.straightdope.com/t/calories-to-support-fat-tissue/646765/3 "2013-01-10T18:39:14Z")
Great, thanks 🙂 ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [January 10, 2013, 9:10pm UTC](https://boards.straightdope.com/t/calories-to-support-fat-tissue/646765/4 "2013-01-10T21:10:11Z")
> [@Darryl\_Lict](#): > > According to [Livestrong](http://www.livestrong.com/article/316732-how-many-calories-does-adipose-tissue-burn-per-day/), 2 calories per pound per day. Note that as mentioned in the link, muscle only burns 6 calories per pound per day, which is more than fat but much less than popularly believed; some people say muscle burns as much as [100 calories per pound per day](http://exercise.about.com/od/exerciseworkouts/f/muscle.htm), which is impossible when you consider than your body is about [40% (skeletal) muscle](http://en.wikipedia.org/wiki/Muscle#Types_of_tissue). Of course, you can exercise that muscle and it will burn more calories. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [January 11, 2013, 2:37pm UTC](https://boards.straightdope.com/t/calories-to-support-fat-tissue/646765/5 "2013-01-11T14:37:19Z")
Here’s another, [more academic source](http://ajcn.nutrition.org/content/82/5/941.full.pdf). FM = Fat Mass. FFM = Fat Free Mass. > [@](#): > > Consistent with previous studies (1–3, 42) the dominant factor > influencing this variation between individuals was the extent to > which the individuals varied in their FFM. The additional role > played by FM as an independent factor influencing BMR has > been a matter of previous debate, with some studies finding a > significant independent effect (4, 5, 43) and others failing to > replicate this result (6, 7). Our studies confirmed that, in this > sample of adults, FM was an independent factor—although the > contribution to the total variance that was explained by differences in FM was relatively small compared with that explained > by FFM. In the derived multiple regression, the coefficient relating BMR to FFM was 0.619, compared with 0.132 for the > coefficient relative to FM. This suggests that each kilogram of > lean tissue exerted about 5 times more effect on BMR than did > each kilogram of fat tissue. This ratio of 5:1 is at odds with in vitro > estimates of the energy metabolism rates of fat and lean tissue [in > both humans (44), and rodents (45)], for which the differences in > energy metabolism between FM and FFM ranged from 10 to 100 > fold. … > > … The coefficient with respect to FM may be greater > than anticipated physiologically because the presence of FM > stimulates the metabolic rate of other tissues as a result of adipokine secretions that are themselves positively associated with > FM. The negative effect of age on BMR, independent of any > age-related changes in body composition reported here, has been > previously reported (3, 47– 49). > Like all previous studies (50 –55), we found enormous variationin between-subject BMR (26% of total variance) that was not > explained by differences in body composition or age (or sex). Which does not quite answer the question directly. What it tells us that most of the variation is based on FFM (which is more than muscle) and that additional fat mass varies BMR 1/5 as much as FFM does, on average. But that lots of BMR variation exists for no as of yet clearly understood reason. [Here is](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2980962/) another stab at it, specifically [this table](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2980962/table/tbl5/). That approach comes up with fat mass contributing 4.5 KCal/kg/d which confirms the 2 KCal/pound number and also may be the source for the 6 calories per pound of skeletal muscle. Kidneys, heart, and brain seem to be the big calorie burners on a per pound basis.