Monday, 28 January 2013

On burning, storing and recomposing.


I couldn't resist!

On my adventures around the interwebs, I've noticed the following:- "Humans aren't Calorimeters. Therefore calories are irrelevant to humans." While I agree with the first sentence, I don't agree with the second one.

Calorimeters burn (oxidise) foods at high temperatures with a flame using oxygen, which produces carbon dioxide, water (depending on what's being burned) & heat energy.

Humans burn (oxidise) foods at 37ºC with enzymes , charge transporters etc using oxygen, which produces carbon dioxide, water (depending on what's being burned), mechanical energy & heat energy.

As both oxygen & carbon dioxide are gases, these can be measured by a respiratory gas analyser, to establish the rate of burning and what's being burned at any instant. See It's all in a day's work (as measured in Joules). When resting, burning occurs at a rate of ~1kcal/minute and, as it's measured while fasted, ~0.11g/min of fat is burned, & ~0.01g/min of carbohydrate is burned. Also note that a lot of mechanical energy can be produced, which can increase the rate of burning by a factor of seventeen.

In conclusion, humans burn (oxidise) foods, though not with a flame, and they can produce mechanical energy in addition to heat energy. The rate of burning and what's being burned at any instant can be measured.


When we eat food, it's digested and absorbed. As a digested meal is absorbed, it appears in the blood as glucose, triglycerides & amino acids. These then disappear from the blood due to burning and storage.

Fig. 1 Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism

Fig. 1 above shows the effects of a 100g Oral Glucose load (▪▫) or a 40g Oral Fat load (●○) on blood glucose level over a period of 360 minutes. Note that subjects are resting during the 360 minutes. As the 100g Oral Glucose load produces a large insulin response (See Fig. 2 below ▪▫), fat-burning is temporarily reduced.
Fig. 2 Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism

Therefore, ~1kcal/minute resting burning rate is derived ~100% from carbohydrate. Therefore, carbohydrate-burning rate is ~0.25g/min. At this rate, it would take ~400 minutes to burn 100g of glucose. If less than 100% of energy is derived from carbohydrate, it would take longer. However, it actually takes ~180 minutes for blood glucose level to fall from maximum to minimum. Therefore, some glucose from the Oral Glucose load is stored (mostly as glycogen in muscles and liver).

Fig. 3B Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism

Fig. 3B above shows the effects of a 40g Oral Fat load (●○) on blood triglyceride (fat) level over a period of 360 minutes. Note that subjects are resting during the 360 minutes. As the 40g Oral Fat load produces no significant insulin response (See Fig. 2 above ●○), fat-burning is unaffected.

Therefore, fat-burning rate is ~0.11g/min. At this rate, it would take ~364 minutes to burn 40g of fat. If less than 100% of energy is derived from fat, it would take longer. Everyone is Different. shows the variation in % of energy from fat at rest. However, it actually takes 180 to 240 minutes for blood triglyceride (fat) level to fall from maximum to minimum. Therefore, some fat from the Oral Fat load is stored (as fat in adipocytes), even though there is no significant insulin response.

Therefore there are times when stuff is stored (anabolism) and there are times when stuff is withdrawn from stores (catabolism). If more stuff is stored than is withdrawn over a period of time, weight goes up, and vice-versa.


After doing intense exercise e.g. sprinting, resistance training with weights etc, muscles become very sensitive to insulin. Therefore, if intense exercise is done just before stuff is stored, amino acids & glucose are preferentially stored in muscles rather than adipocytes. This increases muscle mass relative to fat mass.

If non-intense exercise is done at times when stuff is withdrawn from stores, this maximises the amount of fat withdrawn from adipocytes and minimises the amount of amino acids withdrawn from muscles. This decreases fat mass relative to muscle mass.

It's therefore possible to increase muscle mass at certain times and decrease fat mass at other times, while keeping overall mass relatively constant i.e. it's possible to gain muscle and lose body-fat without being in an overall caloric deficit.

See The Energy Balance Equation, for more information.


Diana said...

Hmmm...."It's therefore possible to increase muscle mass at some times and decrease fat mass at other times while keeping overall mass relatively constant i.e."

I can see the second but not the first. What if I've already reached my maximum genetic potential at adding muscle mass? You know the way trainers are always saying, "ladies, this will not put muscle on you - you can't"? I think the maximum amt. of muscle most women could put on is 5 pounds. I don't know about guys but I think that the vast majority of women are nearly at their genetic potential.

Please disprove this. I would love to be wrong.

Those stories I hear about how someone put 30 pounds of muscle on are invariably young men, who are in their muscle producing age bracket. They should be putting muscle on but weren't cos they were couch potatoes.

Nigel Kinbrum said...

Home at last.

I put a link to Lyle McDonald's site Body Recomposition, as it's crammed with useful information, including What’s My Genetic Muscular Potential?

I believe that most women are nowhere near their maximum genetic potential, as they won't lift heavy weights for fear of looking masculine. It takes Androgenic Anabolic Steroids and/or lowering body-fat too much to make a woman look masculine. In my opinion, of course.

Diana said...

Nigel, Most women are smart not to lift heavy. There's such a thing as tearing ligaments, tendons, overusing same and ending up with sprains & carpal tunnel syndrome, etc. I know: I have a torn supraspinatus and a degraded left bicep tendon from lifting too heavy: all that, and I never got big.

My wrists are 6" around. How big are yours? Women should stick to lighter weights and do body weight pushups. (Pressups to you.)

That said, it's possible for a woman to put on some muscle. I've looked and looked for a real study on this and found only this:;jsessionid=BfftrNmJ8QZjWdzoTKyd.2

The women put on avg. 1.5 kg.

True, the women were over 60. So let's say a younger woman could put on more muscle. Twice as much? 3.0 kg? Not a lot.

Unknown said...

Hey Nigel,

An old friend of mine from the basket ball days wrecked his Achilles tendon while working on his legs. Potential's hardly uniform, eh?

Lyle's got good information on the subject. Although I did find his little clash with Rippetoe over the limitations on rate of gain rather humorous.

Perhaps putting on quicker muscle on a smaller, scrawnier person is easy in the earlier rounds of gaining lean mass.

Nigel Kinbrum said...

Diana, sorry to hear you broke yourself due to lifting too heavy. Did it make you any stronger?

My wrists are 8" round.

The muscle gains in the study you linked to are much lower than in Lyle's article (10-12 lb, or 4.5-5.5 kg in the first year of proper training), but as you point out, the women were over 60. Young women should be able to gain considerably more muscle, as they have higher testosterone levels. Everyone's different, of course.

I brought up the subject of recomposition, as somebody in my blog list (a young woman, funnily enough) stated that eating more food while losing more bodyfat was evidence that calories didn't count.

Diana said...

Nigel, if you take a look at Lyle's website, he not only doesn't give a cite as to how he figured out those gain numbers, he admitted that he essentially made them up.

"I’m not sure if I came up with this idea on my own or stole it from somewhere else (probably a combination of the two) but, in a slightly different context (how quickly can someone gain muscle), I have often thrown out the following values for rates of muscle gain."

What does this mean? It means he doesn't have any evidence to base his table on.

True, the women in the study I found were over 60, but even if you double the amount of muscle a younger woman would gain, it would equate to no more than 6 pounds.

I am in a hurry but I will dig up some studies that include both women and men in these "muscle gain" studies. This is frustrating, but if you assume that the women are the ones at the lower end of the spectrum, it still doesn't amount to much. (Neither do the men, by the way.)

As for whether I got stronger, not a lot. I was never incredibly unfit, and I've never been incredibly fit. I have fairly well developed arm muscles but there is only so much you can do with 6" wrists.

In my one experience doing a hard labor job - a voluntary stint doing trail work in New Hampshire, in the White Mountains (very hard conditions), I noticed that two 70 year old men in our group (admittedly both in great shape, hikers) were way stronger than any of the women. Yes, the women weren't third world women accustomed to hard labor, but then the 70 year olds were also from the pampered West.

If you want hard labor and heavy lifting done, hire a man.

I'm not offended by that - unless I would be offended by the truth.

In short color me a muscle skeptic for men and double that for women.

Nigel Kinbrum said...

On phone again.
As Lyle trains people and knows other trainers, his figures are probably based on his own and others' experience.

Recomposition is the only plausible explanation I can think of that explains how Anastasia can eat more food and lose more body-fat.

Diana said...

Who is Anastasia?

Nigel Kinbrum said...

See Whole30, Goldilocks and evil carbses and the comments.

It gave me the inspiration to write this blog post.

diana said...



I just can't take this N of 1 as proof that women can (a) put on more than a negligible amount of muscle and (2) that you can "eat more, weigh less."


Nigel Kinbrum said...

Diana, I agree. N=1's aren't proof of (or even evidence in support of) anything. Googling "how much muscle can women gain?" shows that mileage can vary hugely.

See also

Diana said...

Nigel, I don't understand what Anastasia's post has to do with this discussion.

Suggestion. Look at table 2.3 in this long study. It's in the middle of the "results" section. Tell me how much muscle the strongly built men put on.

Not a lot. OK?

There are many good reasons to exercise/weight train. Putting on lots of muscle isn't one of them, cause it isn't gonna happen.

You are an engineer, Nigel. Do you go by Newton's laws of mechanics, or Professor Nutjob who says that he's re-written the laws to prove that there is no such thing as drag or wind-shear? (That's the extent of my physics knowledge, please be nice.)

Diana said...

PS I did google "how much muscle can women gain?" and I got the usual popular anecdotal stuff. I cited two scientific studies. Again: I go with Newton, not Professor Nutjob.

Nigel Kinbrum said...

Anastasia claimed that she ate more and got slimmer, therefore calories didn't count. I suggested that NEAT may have increased, but her O/H Jamie insisted that it hadn't. I didn't want to argue!

I thought that muscle mass increase was a possible explanation for Anastasia's anecdote. There is such a thing as muscle memory, whereby previously trained people who reduced/stopped training lost some muscle mass, but then rapidly regained it upon resuming normal training.

The other explanation is that she was eating fewer kcals than she & Jamie estimated and/or she was expending more energy than she & Jamie estimated.

In answer to your questions:-

a) Sweet F/A.
b) Professor...I mean Newton.