Tampilkan postingan dengan label Recomposition. Tampilkan semua postingan
Tampilkan postingan dengan label Recomposition. Tampilkan semua postingan

The Facts of Life.

No, not those Facts of Life!
From http://www.clipartbest.com/stork-carrying-baby

It's becoming painfully obvious that there's a lot of ignorance about certain dietary "Facts of Life". This post will dispel the myths - backed up by evidence, where necessary.

1. Everyone is Different: This has been a recurring theme on my blog, starting in 2009 with the aptly-named Everyone is Different. What this means in practice, is that:-
a) You can't calculate your Energy Expenditure exactly, using one of those fancy equations (e.g. Harris-Benedict).
b) Weight change is proportional to caloric excess/deficit ± inter-personal variation.

2. CALORIES COUNT: If there's zero caloric surplus, there's zero weight gain. There can be water balance shifts due to glycogen shifts, hormonal shifts, electrolyte shifts etc. Somebody fitted a lovely straight line to the weight gain data in Bray et al shows that a calorie *is* a calorie (where weight is concerned), but their line didn't pass through 0,0. Duh!

3. Glycaemic Index (GI) has NOTHING to do with calories: A low-GI carbohydrate still has 4kcals/g. GI is a useful hint as to whether a carbohydrate may disturb blood glucose levels, but it isn't as useful as Glycaemic Load (GL = GI x grams of carbohydrate in the serving). Watermelon has a very high GI, but 100g of watermelon contains only ~5g of carbohydrates, so the GL is less than 5 i.e. watermelon is as safe as houses.

4. Exercise DOESN'T burn as many calories as you think: Exercise is for fitness, not weight loss (unless you're a professional sports-person, who can expend 1,000's of kcals a day in training).

5. Weight loss doesn't ALWAYS result in reduced Basal Metabolic Rate: Whether or not Basal Metabolic Rate reduces with weight loss depends on the degree of Adipocyte Hyperplasia that occurred during weight gain. Humongous weight gain, also weight gain in childhood, increases adipocyte hyperplasia, which is protective against developing T2DM, but makes the subsequent loss of significant amounts of FM more difficult.

6. For Muscle Hypertrophy, a STIMULUS is required: Eating too much food and/or swallowing loads of protein without hypertrophy training doesn't make muscles grow significantly bigger. See http://hillfit.com/. Chris Highcock knows what he's talking about.

7. Yo-yo dieting isn't ALWAYS a bad thing: Bodybuilders (BB'ers) do cycles of "cutting" and "bulking". Cutting is Fat Mass (FM) loss with minimal Lean Body Mass (LBM) loss. Bulking is LBM gain with minimal FM gain.

Non-BB'ers tend to get it the wrong way round. They go on crash diets with insufficient protein intake and lose loads of LBM (which increases weight loss, due to the lower Energy Density of LBM relative to FM). They then eat way too much, gaining weight way too rapidly for much (if any) of it to be LBM, even if they are doing hypertrophy training.

8. FM loss CAN be rapid: See The Rapid Fat Loss Handbook. A Scientific Approach to Crash Dieting.

9. LBM gain CANNOT be rapid: See What’s My Genetic Muscular Potential? to find out how much LBM you can gain and how quickly you can gain it.


Finally, see http://www.bodyrecomposition.com/. What Lyle McDonald doesn't know about fat loss, general nutrition, muscle mass gain and training fits on a postage stamp. He also explains things in language that the sort of person who reads my blog can understand. Just don't leave a comment asking him a question, that's already been answered elsewhere on his site!

On burning, storing and recomposing.

Burning

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 37ÂșC 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.


Storing

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

Figure 1 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 Figure 2), fat-burning temporarily stops. Therefore, the ~1kcal/minute resting burning rate is derived 100% from carbohydrate. Therefore, the carbohydrate-burning rate is ~0.25g/min. At this rate, it would take ~400 minutes to burn 100g of glucose. However, it actually takes ~180 minutes for blood glucose level to fall from maximum to minimum. Therefore, some of the glucose from the Oral Glucose load is stored (mostly as glycogen in muscles and liver).

Figure 3B shows the effects of a 100g Oral Glucose load or 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 Figure 2), fat-burning is unaffected. Therefore, the fat-burning rate is ~0.11g/min. At this rate, it would take ~364 minutes to burn 40g of fat. However, it actually takes 180 to 240 minutes for blood triglyceride (fat) level to fall from maximum to minimum. Therefore, some of the 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.


Recomposing

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 Body Recomposition.