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!

Protein reduces endurance (in mice), food processing vs food refining & Schrödinger.

I saw the following study via Twitter. Dietary protein decreases exercise endurance through rapamycin-sensitive suppression of muscle mitochondria.

Mmm, protein!

Hmmm! In mice, a high protein diet significantly decreased the amount of muscle mitochondria, the mitochondrial activity and the running distance at 50 weeks, although it increased muscle mass and grip power.

A mouse's natural diet is fruit or grain from plants, though mice will eat virtually anything, including Kevlar insulation on wiring. Fruit & grains aren't particularly high in protein, so it's quite possible that eating a sub-optimal diet results in sub-optimal health.

If the results do translate to humans, we have a choice between endurance, and muscle mass & strength in our old-age. I know which I would choose. You'll have to prise the proteins from my cold, dead fingers!

More from Twitter:  A Major Communication Challenge of Our Times: What on Earth Do We Say About Processed Foods? The word "refine/refined" doesn't appear in the above article. I don't have a problem with food processing. What I do have a problem with is food refining. Just after the Mid-Victorian period, it became fashionable to eat foods that had been stripped of "impurities". Goodbye essential co-factors. Hello, degenerative diseases.

Finally, today is the 126th anniversary of Erwin Schrödinger's birthday. I have only one comment:-

Blatantly stolen from http://memegenerator.co/instance/31138345

:-)

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 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.

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.

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.

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 The Energy Balance Equation, for more information.

Use 'em or lose 'em

Hello world. I'm back. The title is referring to our muscles. The following image is from Masters Athletes Show the Importance of Exercise on Aging Muscle..

I'm not going to start doing chronic exercise, but the above is a great incentive to continue with the walking.

I have a hypothesis.

I was keeping quiet about this, as it contradicts Gary Taubes, Michael R Eades & Richard D Feinman and Eugene J Fine.

Please note: This post is not criticising low-carb, high-fat diets. I'm pointing out that if someone on a low-carb, high-fat diet exercises as much gluttony as they want on roast lamb/pork/duck etc, they may not lose as much weight/body fat as they expected & they may even gain.

I don't want to start a shit-storm, but as I am in the "a calorie is a calorie" (when it comes to weight gain/loss) camp and a lot of the people whose blogs I link to aren't, I need to go public. So, here it is, copied and pasted from the comments section of Diet, Carbs, Fat and Weight Loss, corrected for spelling.

"I would like to propose a theory which explains how fat cells can acquire glucose (& thus correct a deficiency in glycerol-3-phosphate) even when serum insulin level is basal.

Consider muscle cells undergoing anaerobic activity:-

Anaerobic activity is very inefficient and uses pyruvate at a very rapid rate. A deficiency in pyruvate up-regulates all of the up-stream processes, including Glu-T4 transporters so as to maximise pyruvate production.

This explains why resistance training with weights greatly increases muscular insulin sensitivity and why resistance training with weights when depleted of muscle glycogen can cause precipitous drops in blood glucose level.

Ditto for glycerol-3-phosphate in fat cells. In this case, blood glucose level is maintained by the liver & kidneys, which convert the glycerol backbone of triacylglycerols (fats) and other substrates such as lactate, pyruvate & glucogenic amino acids into glucose."

In plain terms what this means is that, like muscle cells, fat cells can acquire as much glucose as they need, independently of carbohydrate intake.

Therefore, if an excess (beyond what the body is burning) of dietary fat is eaten, this can be stored in fat cells even if serum insulin level does not increase.

There. I've said it. I expect comments. Moderation is enabled. All comments that are free from ad-hominem, straw men & other logical fallacies will be published.

EDIT: Here's evidence that dietary fat can be stored in the absence of dietary carbohydrate. It involves doing maths on an Oral Fat Tolerance Test:- On burning, storing and recomposing.

EDIT: Here's evidence that a calorie is a calorie (where weight change is concerned):- Bray et al shows that a calorie *is* a calorie (where weight change is concerned).
 
As a lot of people report that they can eat dietary fat without getting fat (& actually getting lighter & slimmer), there appears to be something "magical" going on. It's generally accepted that fat is the least thermogenic of all the macronutrients & protein is the most thermogenic. I wonder if this is the case for all types of fat and all types of people.

See Butyric Acid: an Ancient Controller of Metabolism, Inflammation and Stress Resistance.

From Battle of the Weight Loss Diets: Who's Winning (at losing):-
Insulin Resistant people lose more weight on low-carb, high-fat (LCHF) diets than high-carb, low-fat (HCLF) diets.  
Insulin Sensitive people lose more weight on high-carb, low-fat (HCLF) diets than low-carb, high-fat (LCHF) diets.

According to Gary Taubes's Carbohydrate Insulin Hypothesis, everyone should lose more weight on low-carb, high-fat (LCHF) diets than on high-carb, low-fat (HCLF) diets. Therefore, Gary Taubes's Carbohydrate Insulin Hypothesis is false.

It's possible that in people who do well on LCHF diets, kcals out on the right hand side of the Energy Balance Equation increase significantly. So keep on keeping on.

EDIT: With the benefit of four more years of knowledge, here's why LCHF & ketogenic diets have an advantage for people who have Insulin Resistance. How low-carbohydrate diets result in more weight loss than high-carbohydrate diets for people with Insulin Resistance or Type 2 Diabetes.

See also:-
Metabolic Advantage of Ketogenic Diets Debunked? An Intriguing Study You Will Want to Read
Is the Fable of Unfettered Fat Burning Derailing Your Low Carb Diet?

See also How stuff works & Enzymes.