Nutritional Ketosis: What is it good for?

I have a video in mind...


Having previously shown you what I look like on a diet of ~125g/day low-GL carbohydrates, here are a couple of recent pictures of Jimmy Moore, who's on a very-low-carb, very-high-fat diet (~85%E from fats), a.k.a. Nutritional Ketosis. It involves adding Kerrygold butter to just about everything, even eating sticks of it from a block. I'm not kidding.

I told you I wasn't kidding.

From Google Image Search on "Jimmy Moore" OR "Livin la Vida low carb", images in the last 7 days:-

On 6.7.14.

On 8.7.14.

The only recent footage of Fredrick Hahn, is the following video from the Low Carb Cruise...


To my eyes, Nutritional Ketosis is good for absolutely nothing. Dietary fat can be stored as body fat, in the absence of dietary carbohydrates. Gary Taubes' claim "You can basically exercise as much gluttony as you want, as long as you're eating (only) fat and protein." is pure fantasy, not supported by evidence.

The low protein intake in Nutritional Ketosis, combined with the high serum cortisol that's almost inevitable on this way of eating, results in a loss of muscle mass. I give Nutritional Ketosis a thumbs-down.
 

Summary:-

1) No Energy Deficit → No Weight Loss. There is no Metabolic Advantage to Nutritional Ketosis. See http://www.jbc.org/content/92/3/679.full.pdf

2) Insufficient carbohydrate intake and insufficient protein intake starves the liver & kidneys of gluconeogenic pre-cursors, which raises cortisol, which converts muscle mass into gluconeogenic pre-cursors e.g. Glutamine, Alanine etc. This is standard Biochemistry. No links required.

3) While excess carbohydrates are converted into triglycerides by the liver, excess fats are converted into cholesterol by the liver, which is exported to tissues as LDL-C.

LDL-P ∝ LDL-C. High LDL-P is strongly associated with increased risk factor for CHD. See http://www.lecturepad.org/dayspring/lipidaholics/pdf/LipidaholicsCase291.pdf

CHD is not an inflammation-mediated phenomenon. It's an LDL-P and neovascularisation-mediated phenomenon. See http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3492120/

Postprandial lipaemia is atherogenic. See Ultra-high-fat (~80%) diets: The good, the bad and the ugly.

4) Read Page 10 of https://www.drmcdougall.com/misc/2013nl/feb/pritikinpdf3.pdf, starting from "Could such a cream meal precipitate an angina attack because the oxygen-carrying capacity of the blood is lowered?" It's an actual trial on humans with clogged coronary arteries. It's not a hypothesis.

5) Chronically-raised cortisol causes aggressive behaviour (cortisol is a stress hormone) and adversely affects short-term memory storage in the Hippocampus. See http://evolutionarypsychiatry.blogspot.co.uk/search?q=cortisol

6) Eskimos, Sami, Masai, Samburu, Tokelauans etc, get ~50% of their total energy from fats. There are zero populations that get ≥80%E from fats.


Update 25th July 2014: I appear to have rustled Fredrick Hahn's Jimmies. See https://www.facebook.com/FredrickHahn/posts/10152227780827864

I can safely state that Fredrick Hahn is a liar (I am not poking fun at anybody and I have only blocked him (not his followers) from posting here, for a flagrant breach of my Moderation Policy on his first attempt at commenting), and intellectually-dishonest (for repeatedly mis-quoting me, and using other logical fallacies). He posted the above post knowing that, as I had blocked him on Facebook, I wouldn't see it. I only learned of its existence after a friend PM'ed me on Facebook Messenger. He instructed his "followers" to leave comments here and then accuse me of lying about white-listing, back on his page, because their comments didn't appear immediately. He's a real piece of work! From ABOUT ME:-

Moderation Policy: Comments from first-time & untrusted commenters are moderated ← (click for details). Please be patient. Now that I have a Smart Phone, I can publish your comments during the day when I'm away from my lap-top, but I prefer to type replies on my lap-top. Comments from anonymous commenters, containing links in any form, are deleted.

This is a function of Disqus, as it's impossible to retrospectively white-list a commenter who's never commented here before. There appears to be a severe lack of cognitive function in these people. I really can't think why that is ;-)

Why am I being so hard on Jimmy Moore and Fredrick Hahn? I don't know these people personally.

1) These people are making money out of peddling pseudoscience.

2) These people meet all the criteria in Guest post: Science versus Pseudoscience and have created an alternative science, where sky-high LDL cholesterol, sky-high LDL-P and sky-high postprandial TG's are not risk factors for CHD, but are either harmless or beneficial.

Bray et al shows that a calorie *is* a calorie (where weight change is concerned).

Continued from Everyone is Different, Part 3.

EDIT: I made an error in stating that all of the extra calories came from fat, in the fat overfeeding phase. Thanks to commenter CynicalEng for pointing that out. It doesn't change the conclusion at all.

At 01:17 on 6th June, during a Facebook discussion, Fred Hahn told me:-
"Nigel Kinbrum - read this please.
Bray, et al. Shows that a Calorie is Not a Calorie and that Dietary Carbohydrate Controls Fat Storage.
Perhaps you'll learn something from a real expert who teaches metabolism to medical students at the largest medical school in the country."

So I did.

At 02:22, I replied:-
"Thanks for that. I read Feinman's blog post about Bray et al https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3777747/ some time ago.
There's a fundamental error in Feinman's analysis. As LeonRover pointed out in his comment https://feinmantheother.com/.../bray-et-al-shows-that.../...
In Diets:- "Absolute carbohydrate intake was kept constant throughout the study."
Also, in COMMENT:- "The extra calories in our study were fed as fat, as in several other studies, and were stored as fat..."
Oh, whoops! That may be why it was rejected by the editor."

Here's Figure 6 from Bray's study.

From https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3777747/

Some Definitions:-

LBM = Lean Body Mass
FM = Fat Mass = Body Fat

Weight change = (LBM change + FM change)

Weight change varies from ~+3.5kg (@ +2,500kJ/d) to ~+9.1kg (@ +5,900kJ/d).

(Maximum weight increase)/(minimum weight increase) = 2.6
(Maximum kJ/day increase)/(minimum kJ/day increase) = 2.36

∴ A calorie *is* a calorie (where weight change is concerned) ± some inter-personal variation.
∴ Insufficient protein can result in LBM loss (this is bad).

As LBM has a lower Energy Density (~600kcals/lb) than FM (~3,500kcals/lb),  LBM loss can increase weight loss, when in a Caloric Deficit.

See The Energy Balance Equation, for a simple explanation, and The Dynamics of Human Body Weight Change, for an incredibly complicated one!


I was rather chuffed when Alan Aragon left the following comment at 04:34:-
"Nigel is correct. From Bray et al's text:
"The extra calories in our study were fed as fat, as in several other studies [33,34], and stored as fat with the lower percentage of excess calories appearing as fat in the high (25%) protein diet group. The higher fat intake in the low protein group probably reduced nutrient absorption (metabolizable energy) relative to the other groups and this would have brought the intake and expenditure closer together in this group.""

Feinman has deleted his blog post. However, his post I Told George Bray How to do it Right is still there. I believe that Dr. George A. Bray M.D. sort-of did it right.

Dr. George A. Bray used a "weight maintenance formula" in all three groups for the weight maintenance phase. He then changed the formula in all three groups to low-P, med-P and high-P formulas, for the fat overfeeding phase. Carbohydrate grams remained constant in all three groups for all phases, but additional fat grams were fewer in the high-P group than in the low-P group, for the fat overfeeding phase.

I would have used the low-P, med-P and high-P formulas for the weight maintenance phase and for the fat overfeeding phase, to equalise the additional fat grams in all three groups.

Continued on Everyone is different Part 4, Fallacies and another rant!

Completing the trine: vive la différence!

First, the obligatory picture of Hannah Spearritt :-)

Women have a harder time losing weight than men. Women retain water more than men for hormonal reasons, but a factor that's overlooked is that, on average, healthy women have higher body-fat percentages than healthy men. This is because women have babies and men don't. Who knew? On the plus side, women produce more DHA than men.

Why should having higher body-fat percentages make a difference to weight loss? See What is the required energy deficit per unit weight loss? The energy deficit required to lose 1lb of body-weight increases with increasing body-fat percentage. It's rarely 3,500kcals per lb.

If you really love mathematics, see The Dynamics of Human Body Weight Change by Carson C. Chow and Kevin D. Hall.

From the above paper:- ΔU = ΔQ - ΔW

where ΔU is the change in stored energy in the body, ΔQ is a change in energy input or intake, and ΔW is a change in energy output or expenditure. This is the Energy Balance Equation. As I said back in Back to black, CIAB, pharmaceutical drug deficiencies & nerds.

Where body weight is concerned, calories count (but don't bother trying to count them).
Where body composition is concerned, partitioning counts.
Where health is concerned, macronutrient ratios, EFAs, minerals, vitamins & lifestyles count.

N.B. Poor health can adversely affect body weight and/or body composition, by increasing appetite and/or by adversely affecting partitioning.

Bursting from the seams: "Obese adipocytes" literally "explode" and leave a nasty inflammatory mess.

I just read a Public post on Facebook from someone I follow and whose blog is in my list.

https://www.facebook.com/profdrandro/posts/533941643320863

It contained a word that I've never seen before, but would like to see more often - Pyroptosis. 
See Obese adipocytes show ultrastructural features of stressed cells and die of pyroptosis.

Adipocytes dying, huh? You know what that means? Loss of body-fat. Unfortunately, there is an issue with the nasty inflammatory mess left, after adipocytes "explode". This limits the rate at which adipocytes can be "exploded".

See also SuppVersity Cellulite Special: The Etiology of Cellulite, Genetical and Behavioural Risk Factors? Physical and Supplemental Treatment Strategies & Their Efficacy. Warning! Not Safe For Work, due to pictures of naked botties.

Adipocyte Hyperplasia - Good or Bad?

The answer is "It depends!".

The above plot is from Fig. 4 of Cytokine-mediated modulation of leptin and adiponectin secretion during in vitro adipogenesis: Evidence that tumor necrosis factor-α- and interleukin-1β-treated human preadipocytes are potent leptin producers and shows that leptin secretion from adipocytes increases non-linearly with increasing culture period.

As adipocytes fill, there's insignificant leptin secretion up to a certain level of fullness. Above that level of fullness, leptin secretion increases non-linearly. What this means is that reducing adipocyte fullness by x% reduces leptin secretion by more than x%.

If adipocytes become full due to a chronic caloric excess, there are two possibilities.

1a: If there is continued caloric excess, no preadipocytes are converted into adipocytes. There is no additional storage capacity available for excess nutrients, so they remain in circulation. T2DM has developed = bad.

1b: If there is subsequent caloric deficit, adipocytes start to deplete, storage capacity becomes available and T2DM goes away (if beta cells haven't been destroyed). The low number of fairly full adipocytes secrete sufficient leptin, so metabolic rate is high and hunger is low = good.
EDIT: This is the principle behind the DiRECT protocol.

2a: If there is continued caloric excess, pre-adipocytes are converted into adipocytes. This is adipocyte hyperplasia. There is additional storage capacity available for excess nutrients, so T2DM doesn't develop = good.

2b: If there is subsequent caloric deficit, adipocytes start to deplete. However, there are more adipocytes than in 1b, so for a given fat mass, adipocytes are less full than in 1b. The higher number of less full adipocytes secrete less leptin than in 1b, so metabolic rate is lower and hunger is higher than in 1b = bad.

Adipocyte hyperplasia is good for preventing T2DM as fat mass increases, but bad for metabolic rate and hunger after subsequent fat mass loss. Children are growing, so have adipocyte hyperplasia. Adults aren't growing, so have less/no adipocyte hyperplasia. Therefore, adipocyte hyperplasia during childhood will result in some protection from developing T2DM, but life-long misery due to increased hunger and reduced metabolic rate after subsequent fat mass loss. This is why I believe that children need to be protected from the persuasive marketing of manufacturers of CIAB (Crap-in-a-Bag/Box/Bottle).

See Beradinelli-Seip Syndrome – stick that in your pipe and smoke it and read the comments to see why adults with insufficient adipocytes are highly likely to develop T2DM. This is why Asians who remain skinny in childhood (so have no adipocyte hyperplasia) have a high risk of developing T2DM. Sumo wrestlers are Asians who become fat in childhood (so they have a lot of adipocyte hyperplasia) so they have a lower risk of developing T2DM.

According to Adipocyte Turnover: Relevance to Human Adipose Tissue Morphology:-
"Occurrence of hyperplasia (negative morphology value) or hypertrophy (positive morphology value) was independent of sex and body weight but correlated with fasting plasma insulin levels and insulin sensitivity, independent of adipocyte volume (β-coefficient = 0.3, P < 0.0001). Total adipocyte number and morphology were negatively related (r = −0.66); i.e., the total adipocyte number was greatest in pronounced hyperplasia and smallest in pronounced hypertrophy. The absolute number of new adipocytes generated each year was 70% lower (P < 0.001) in hypertrophy than in hyperplasia, and individual values for adipocyte generation and morphology were strongly related (r = 0.7, P < 0.001). The relative death rate (∼10% per year) or mean age of adipocytes (∼10 years) was not correlated with morphology."

If you want to remain slim, high fasting serum insulin due to hepatic and/or muscular insulin resistance and/or chronic overconsumption is bad.

Eat Less, Move More: Solutions to problems.

The fact is, in order to lose weight and be healthy, we need to Eat Less, Move More. The problem is that most people (apart from bodybuilders) just can't/won't do it consciously. In Determinants of the Variability in Human Body-fat Percentage, I listed a number of reasons why people eat what (and as much as) they do. Here are some solutions to the problems that cause over-eating and under-moving.

1) Parents: If you've been raised to be a plate-clearer, use a small plate which makes a small amount of food look like more.

2) Genetics: Eat foods that satisfy your appetite for as long as possible. You have to find out what they are by experimentation, as everybody is different.

3) Peer pressure from parents, siblings, friends, business partners & significant others: Thank them but politely decline. If they persist, reduce the level of politeness until they get the message.

4) Religion/tradition: Start a new tradition of not stuffing yourself silly at religious festivals. Then spread the word!

5) Culture: Try new foods. They won't kill you and they may actually taste good. Learn to cook. Herbs and spices or a splash of Worcestershire/Sweet Chilli Sauce can make horribly-bland foods (e.g. boiled/steamed rice) eatable.

6) Time: Be prepared. Pack a lunch-box with sufficient provisions to get you through the working day/night. Microwave cooking/heating saves a lot of time. It only destroys nutrients if you add a lot of water to the food before cooking (which is not necessary) and then throw the water away after cooking, or overcook foods. All cooking methods that raise the temperature of food to >70°C denature proteins. Denaturing proteins only changes their 3-D structure, which actually makes them easier to digest.

7) Habit: Habits can be changed.

8) Media: When an advert for something moreish is broadcast, flip channels for 30 seconds or if that's not possible, look away and hum a tune to mask the sound. Make sure that there's no food in sight while watching TV to prevent mindless nibbling. Keep a bottle of low-calorie drink nearby to sip on regularly. EDIT: I now watch TV on my computer with Ad-blocking, which eliminates all TV adverts.

9) Physiological & psychological reasons: Maintain a stable blood glucose level by not eating foods that are made mostly out of grain dust (a.k.a. flour) and/or sugar and/or other refined carbohydrates. If you're very active and you need to eat a lot of carbohydrate, choose grains that still look like grains (e.g. rolled oats, rice, quinoa etc), fruits, shoots, roots and tubers. Either get sufficient sun exposure or supplement with ~5,000iu/day Vitamin D3 to reduce the risk of low mood due to Seasonal Affective Disorder. The long-chain omega-3 fats in oily fish help to stabilise mood. Magnesium helps to reduce anxiety (also muscle cramps).

10) Allergies & intolerances: Avoid foods that are very moreish.

11) Geography: Eat locally-grown foods from Farmers' Markets, where possible.

12) Season: Eat foods that are in season, where possible.

13) Boredom: Keep busy. Do something!

14) Exercise: This has always been a problem for me. Exercise used to make me hungry, resulting in me eating more calories than I burned exercising. Solution: If I dress warmly enough, that stops me from getting the munchies due to feeling too cold.

15) Beliefs: I'm not going to try to change your beliefs.

16) Senses: Avoid supermarket aisles that contain junk foods. What your eye can't see and your nose can't smell, your heart won't grieve over.

17) Hunger: Don't let yourself become really hungry as that encourages over-eating when you do finally eat. Don't go food shopping when you're hungry, as that encourages the buying of junk foods.

18) Comfort: Don't buy larger clothes/loosen your belt. If your clothes are getting tighter, let that suppress your appetite. If your clothes are getting looser, buy smaller clothes and/or tighten your belt. Never loosen it.

19) Shame/Self-loathing: If that suppresses your appetite, make the most of it.

20) Current fatness: N/A.

21) Willpower: Hopefully, the above solutions will help you to resist temptation.

I hope that you all had a good Christmas/whatever.

Continued on Move More: Solutions to problems.

Determinants of the Variability in Human Body-fat Percentage.

There are extremely skinny people, very skinny people, skinny people, average people, fat people, very fat people and extremely fat people. However, all healthy newborns have roughly the same body-fat percentage.

As we grow, we gain weight. That's normal. However, the percentage of our bodies that's body-fat can and does change. I'm not going to start another pointless "is a calorie a calorie?" debate as whether it is (as I believe) or it isn't (as others believe), isn't particularly relevant.


What makes some people gain more body-fat mass & less muscle mass than others?

Where nutrients end up depends on the relative insulin sensitivity of the target tissues.
Fat cells are usually always sensitive to insulin unless they are so full of fat that they cannot accommodate any more, in which case either pre-fat cells get turned into new empty fat cells, or if there are no pre-fat cells left, the result is type 2 diabetes.

Muscle cells vary in their sensitivity to insulin. Inactivity lowers insulin sensitivity and intense exercise increases it. Body-builders do a lot of intense exercise so as to maximise muscle cell insulin sensitivity in order to get the maximum amount of nutrients into muscle cells rather than fat cells.

Liver cells vary in their sensitivity to insulin depending on how full of glycogen they are and how much visceral fat (fat around the internal organs) there is.


What makes our weight go up?

1) Eating
2) Drinking
3) Putting on clothes
4) Oxygen breathed in


What makes our weight go down?

1) Defaecating
2) Urinating
3) Taking off clothes
4) Carbon dioxide & water vapour breathed out
5) Energy losses due to movement & heat losses due to conduction, convection, radiation & evaporation
6) Miscellaneous (loss of various bodily fluids, loss of skin cells/hairs/nails, ketones in urine/sweat/breath)

Some factors are controllable/reversible and some aren't. Over a period of 24 hours, our weight goes up and down by a few pounds due to the above factors. Whether our average weight over a 24 hour period changes over the course of days, weeks, months & years depends on the balance between the things that make it go up and the things that make it go down.


Why do we eat & drink what (and as much as) we do?

1) Parents
When we are young, what & how much we eat is determined by our parents (also schools). They dictate the foods and the portion sizes. Poor parents (also schools) often buy the cheapest possible foods. Poor parents encourage "plate-clearing" as they cannot afford waste.

2) Genetics
Some of our ancestors lived in hot countries and some lived in cold countries. Some habitually ate meats and some habitually ate shoots or roots or fruits or grains. This has an effect on our bodies. My ancestors came mostly from Northern Europe which may explain why I achieve better appetite control on a meat-based diet rather than a grain-based diet. The ability to digest lactose (milk sugar) is determined by the habitual milk-drinking in adulthood of our ancestors. Only 4.7% of white English people are lactose-intolerant compared to ~98% of Africans, who would have drunk warm raw milk that had lactase in it.

3) Peer pressure from parents, siblings, friends, business partners & significant others
"Go on! One (more) *insert name of junk food/drink here* won't hurt!"

4) Religion/tradition
It's become commonplace for English people to stuff themselves silly at Christmas, eat lots of chocolate eggs at Easter, pancakes etc.

5) Culture
Certain foods that are very nutritious are either culturally-unacceptable or have fallen out of favour e.g. rabbit/horse/cat/dog-meats & offal (brains, stomachs, lungs, pancreases, hearts, kidneys, bladders, necks, feet).

6) Time
Increasingly busy lives make some people buy pre-prepared meals/snacks which are usually refined carbohydrate-based e.g sandwiches, Subway/Maccy D/BK/KFC. Some workers only have access to vending machine foods & drinks or canteen food which may be of dubious quality. Others blow-out on business lunches.

7) Habit
How many people eat by the clock rather than when they are hungry? School children & many workers have no choice and have to eat at set meal times.

8) Media
There are lots of cookery programmes with celebrity chefs endorsing some diet or other and TV adverts for all sorts of manufactured foods but not many adverts for meat, poultry, fish, eggs, cheese etc (whatever happened to "Beefy & Lamby" & "Go to work on an egg"?). There's always some "expert" telling us what to eat & what not to eat. A lot of mindless eating occurs while watching TV.

9) Physiological & psychological reasons
When we're feeling ill, sad or depressed or have unstable blood glucose levels, we may fancy foods which are high in sugar and fat (mmm, chocolate!). People who are very sedentary and/or lacking sufficient Vitamin D may have unstable blood glucose & insulin levels resulting in extreme lethargy after meals followed by ravenous hunger. People with Anorexia Nervosa often starve themselves or purge after meals.

10) Allergies & intolerances
People avoid foods that make them feel ill.

11) Geography
If we live in a country that grows a lot of a certain foodstuff e.g. rice, wheat, beetroot etc, we are encouraged to eat a lot of that particular foodstuff. When we feel hot, our appetites decrease and when we feel cold, our appetites increase. This is why we don't get fat when we put more clothes on to make ourselves feel warmer.

12) Season
This isn't so relevant, now that most foods are transported around the world and sold in supermarkets, but locally-grown seasonal foods bought from farmers' markets are tasty & nutritious.

13) Boredom
The saying "the Devil makes work for idle hands" applies to our brains & stomachs as well.

14) Exercise
Some people's appetites decrease when they exercise and some increase. I used to fall into the latter category. Over-training at high-intensity on insufficient carbohydrate intake can drain muscle glycogen to the point where muscles rapidly suck glucose from the blood causing low blood glucose. Apart from faints, shakes & sweats, this hugely increases appetite as the brain is crying out for something to raise blood glucose a.s.a.p.

15) Beliefs
Lacto-ovo-vegetarians, pescatarians, vegetarians, vegans etc will not eat certain foods for ethical/moral reasons.

16) Senses
The sight & smell of food & the sound of food cooking can increase our appetites. TV adverts and supermarkets use this to increase sales.

17) Hunger
The emptier the stomach is, the more ghrelin it secretes, which increases our appetites.

18) Comfort
If clothing becomes uncomfortably tight around the waist, that can suppress our appetites. Keep your belt on the same hole, to discourage over-eating.

19) Self Shaming
If we catch sight of our bodies in a mirror and don't like what we see, that can suppress our appetites. People who have Anorexia Nervosa see their bodies as fat/obese when they are actually skinny/emaciated.

20) Societal Shaming
In Japan, it's frowned upon to be too fat. Ditto in "Rich" areas of some countries. Fat-shaming can suppress appetite.

21) Current fatness
As we get fatter, fat cells secrete more leptin, which suppresses our appetites. Very fat people's fat cells secrete so much leptin that the brain can become insensitive to it, resulting in poor appetite suppression.

22) Willpower
Some people find it harder than others to resist the enticements listed above to eat/drink more calorie-dense, nutrient-poor junk.


If I've left anything off this list, feel free to comment. Our bodies are pretty complicated and contain many regulatory Negative Feed-Back (NFB) loops, so we humans have managed to survive famines & disasters over the aeons by our ability to store an excess of proteins, carbohydrates & fats as muscle & body-fat (also food in food-stores) and are now at the top of the food chain (except in lion, tiger, wolf, hyena, bear & shark territory!). Our biggest threat today is excessively-cheap & over-promoted manufactured foods which are calorie-dense & moreish and lifestyles that encourage us to over-eat, under-move and under-sun our skins. When people get too fat, their blood glucose control becomes impaired, which encourages even more over-eating and under-moving, thus creating a vicious circle.

I think that manufactured foods should be taxed and the revenue used to subsidise natural foods. One problem with such a plan is that the Government doesn't always use revenue for the purpose intended e.g. Road Tax. Another problem is in defining manufactured foods e.g. does churning milk to make butter count as manufacturing? Ditto pressing olives to make EVOO? I personally think not, but it's a grey area.

I also think that there should be a ban on the advertising of manufactured foods, as adverts encourage us to buy & consume foods we don't need. Marketing is more persuasive than you think.

See also Eat Less, Move More: Solutions to problems.

Everyone is Different.

If there's one thing I've learned over the years of research into Diet and Nutrition, it's this: Everyone is Different. When I first discovered low-carbohydrate diets (thanks to the late Dr Robert C. Atkins M.D.), I thought that it was the One True Diet, and I became a bit of an "Atkins bore" telling everyone how wonderful it was and suggesting that everyone should be on it. I now know that what suits me* doesn't necessarily suit everyone else.

*It only suited me because I had Insulin Resistance/Metabolic Syndrome/Syndrome-X. I reversed it in 2008. See Insulin Resistance: Solutions to problems for how I did it.

Here's Fig. 2 from Determinants of the variability in respiratory exchange ratio at rest and during exercise in trained athletes. Used with permission.

Respiratory Exchange Ratio (RER) (a.k.a. Respiratory Quotient (RQ)) is the ratio of carbon dioxide breathed out to oxygen breathed in. This ratio depends on the fuels that the body is burning for energy. For example, if the body is burning 100% fats, RER = 0.7. If the body is burning 100% carbohydrates aerobically, RER=1.0. If the body is burning 100% carbohydrates, with some aerobically and some anaerobically (e.g. sprinting flat-out), RER > 1.0. To understand why this is so, see Respiratory Exchange Ratio (RER) explained.

RER varies with intensity of exercise, food intake (increasing protein &/or carbohydrate intake increases it and fasting or reducing protein &/or carbohydrate intake reduces it) and cardiovascular fitness. Increasing cardiovascular fitness reduces RER.

The top diagram is a histogram of fasted RER and % fat oxidation vs. number of subjects. At the left-hand end of the histogram, there are two cyclists with a fat oxidation of 93 - 100%. At the right-hand end of the histogram, there is one cyclist with a fat oxidation of 20 - 27%. Average fat oxidation is ~60%.

As exercise intensity increases, the peak in the histogram shifts to the right as shown in the lower diagram. At 25% of maximum intensity, mean fat oxidation is ~53%. At 50% of maximum intensity, mean fat oxidation is ~37% and at 75% of maximum intensity, mean fat oxidation is ~13%. At maximum intensity, mean fat oxidation is ~0% i.e. 100% of energy is obtained from carbohydrates when sprinting flat-out. Somebody on a very-low-carbohydrate, high fat ketogenic diet e.g. Atkins induction (~20g net carbs/day) could keel over with hypoglycaemia if they exercise for too long at too high an intensity.

As there is variation from person to person, you must find out for yourself your own optimum proportions of proteins, fats & carbohydrates, and these depend upon the intensity & volume of exercise you do. It sounds complicated, but it isn't really.

Apply the principle of "Eat, monitor & adjust accordingly" as Toxic Toffee (ex-Muscletalk member) always used to say. The eating bit will be covered in future Blog posts. The monitoring bit doesn't necessarily involve bathroom scales.

Hang on. Isn't "dieting" all about losing excess weight? Not necessarily. Remember the old joke?
Q. What's the best way to lose 5lbs of ugly flab?
A. Cut off your head.
As your body contains water, muscle, bodyfat, bones, cartilage, tendons, organs, glycogen, skin etc and your scales can't tell the difference between them, losing weight the wrong way can make you less healthy. However, losing weight the right way will make you more healthy.

If you starve, skip breakfast or go for a long run before breakfast, as your body is lacking glycogen reserves & amino acids, a large amount of a corticosteroid hormone called cortisol is secreted, which increases the conversion of muscle into amino acids, then glucose. As muscle has an energy density of ~600kcal/lb, a deficit of 3,500kcal (which would result in a bodyfat loss of 1lb) results in a muscle loss of 5.8lb. For more information, see The Energy Balance Equation.

Chronically-high cortisol also suppresses the immune system and weakens skin & bones.

Unless you have a lot of muscle mass to spare, it's bodyfat that you should be losing, and to monitor this, either use a tape-measure around your waist, check how loose/tight your clothes are, or strip-off and jump up & down in front of a full-length mirror. As Big Les (Muscletalk Moderator) says, "If it jiggles, it's fat.".

2016 EDIT: Scales that can calculate bodyfat % etc are now inexpensive, e.g. Body Analysis Scale.

So, what happens if you eat too much carbohydrate but your body doesn't burn it fast enough? Initially, carbohydrate intake tops-up liver and muscle glycogen stores, which increases carbohydrate-burning to compensate. The liver can store about 70g of glycogen and muscles can store about 400g of glycogen. If, despite increased carbohydrate-burning, more carbohydrate is consumed than is burned, glycogen stores continue to fill. When glycogen stores become full, RER increases to 1.0 and 100% of energy is derived from carbohydrate. Getting 100% of energy from carbohydrate means that zero fat is burned, so keeping glycogen stores filled to the brim by chronically overeating carbohydrate is not a good idea if you want to burn some body-fat.

Once glycogen stores are full, any additional intake of carbohydrate beyond that which is burned passes through the lipogenesis pathway - this basically means that carbs are turned into fat - which may end up as liver fat. But there's even worse news. Fat is secreted by the liver into the blood as triglycerides. This is bad for the cholesterol particles in your blood. See Cholesterol and Coronary Heart Disease. What happens if you eat too few carbs? As stated above, someone exercising at a highish intensity taking in insufficient carbohydrates could get hypoglycaemia & keel over.

How many grams of carbohydrate per day does it take to promote lipogenesis? Someone at rest burns ~1kcal/minute. If this is derived 100% from carbohydrate, this is equivalent to 0.25g of carbohydrate/minute, or 15g of carbohydrate/hour, or 360g of carbohydrate/day. Therefore, sedentary people who chronically consume more than 360g of carbohydrate/day may produce significant triglycerides. People who have The Metabolic Syndrome/Syndrome-X (a high proportion of people who have excess belly fat) have increased lipogenesis and higher serum triglycerides than healthy people.

Discussing weight again for a moment, it's often said that all diets are the same, as weight loss is all about calories. This is true. See Is a Calorie a Calorie? However, body composition is determined by a combination of macro-nutrient proportions (i.e. the relative amounts of proteins, carbohydrates and fats in the diet) and the intensity & volume of exercise. Health is determined by a combination of micro-nutrient proportions (i.e. vitamins, minerals & anutrients) and exercise. See On burning, storing and recomposing.

If you're only interested in weight loss, just count calories. If  you wish to lose bodyfat without losing muscle mass, you need to know what proportions of proteins, carbohydrates & fats to eat (it's really not that critical, but many people get it wrong). You need to know the difference between good carbs & bad carbs, and good fats & bad fats. You need to know the best times to eat proteins, carbohydrates & fats relative to exercise (it's also really not that critical, but many people get it wrong). You need to know the difference between good exercise & bad exercise.

Continued on We are not all the same.