Sunday, 20 May 2012

high CHO vs high FAT dieting

I stumbled across this old paper ( 1964 ) recently, sometimes these old papers can be real gems because the scientists of old were probably less influenced by bias, political correctness, and corporate/financial motivation. I dont have access to the full paper which is a shame, so im left with decrypting the abstract. BEWARE! He talks about mice again. Extrapolate to humans at your own risk!

The rate of weight loss in mice produced by restricting calorie intake below normal requirements is influenced by the type of food predominating in the diet; fat producing a rapid loss and carbohydrate a slower one.
I.E. a calorie is a calorie.

oh wait..

The amount of weight loss in both instances can be accounted for almost entirely by the extent of the negative carbon balances.
This is just basic common sense. To lose weight, you must expelle more carbon atoms than you ingest.

The varying rates of weight loss are due to differences in the rate of fat loss and not to changes in total body water.

Dont listen to this guy!, common knowledge is right, you only lose water on atkins diet!

In mice on a normal diet and in carbon equilibrium, about half the carbon is excreted as CO2 and half in the form of organic molecules with an energy value of their own.

I.E. the body wastes calories. This is why its foolish to talk about energy balance and calories in calories out, it only makes sense to talk about carbon balance.

With restricted calorie high carbohydrate diets the proportion excreted as CO2 rises to over 80 per cent of the total while the proportion excreted in the form of complex molecules falls.

What this basically says is that on a low calorie high carb diet, your body becomes EXTREMELY efficient, and most nearly all carbon atoms are completely oxidated to CO2 before being expelled from the body. Being efficient is not something you want if your to trying to reduce something. ( fat mass )

With restricted calorie high fat diets the proportion excreted as CO2 remains normal. The half excreted as complex organic moleceules is significantly altered as to its distribution between feces and urine.

Now this is a tricky statement to dissect without the full paper. We know that ketones are excreted in breath and urine on a ketogenic diet, but whats this stuff about feces excretion of carbon atoms? Can you shit out calories? Maybe it only happens if your a mouse?

With restricted calorie feeding the proportion of food and/or tissue totally degraded to CO2 influences the amount of energy available to the organism.
I would re-word this to "with restricted nutrient feeding". Total calories consumed are not so as important as amount of carb/protein/fat consumed. Things make more sense when you consider the next statement....

The demands on its own fat stores are consequently greater when fat is the major constituent of such a diet.
Again the way I would look at this is that, "the demand on fat stores is greater when protein and carbs are only very small parts of the diet". It does seem to me that researchers are hesitant to admit when the calories in calories out model fails to predict something. Remember the monkey study where the researchers lost some calories?

This next paper is a good example of that.....

The role of energy expenditure in the differential weight loss in obese women on low-fat and low-carbohydrate diets.

We have recently reported that obese women randomized to a low-carbohydrate diet lost more than twice as much weight as those following a low-fat diet over 6 months.
All lies, a calorie is a calorie.

The difference in weight loss was not explained by differences in energy intake because women on the two diets reported similar daily energy consumption.
Remember we are scientists! And calories in calories out is a universal truth and law! it must be obeyed at all time! If the groups had the same energy intake, the low-carb group must of had higher energy expenditure!!!!

We hypothesized that chronic ingestion of a low-carbohydrate diet increases energy expenditure relative to a low-fat diet and that this accounts for the differential weight loss.
Yuh, because, calories dont vanish.

So anyway, after this the scientists measure various energy expenditures including basal metabolic rate ( which we have already seen does not predict adiposity ), thermic food affect, and physical activity. The researchers had this to say next....

Mean REE in the two groups was comparable at baseline, decreased with weight loss, and did not differ at 2 or 4 months. The low-fat meal caused a greater 5-h increase in TEF than did the low-carbohydrate meal . Estimates of physical activity were stable in the dieters during the study and did not differ between groups.
OK, OK, that can ONLY mean one thing!, food intake was the same, energy expenditure was similiar, so that means.......................................drum roll

The differential weight loss is not explained by differences in REE, TEF, or physical activity and likely reflects underreporting of food consumption by the low-fat dieters.
I.E. fat people are fucking liars!!!!


  1. For some reason, I can't access the full text of this paper even though my library says we should have access from 1964 onwards.

  2. "Remember we are scientists! And calories in calories out is a universal truth and law! it must be obeyed at all time! If the groups had the same energy intake, the low-carb group must of had higher energy expenditure!!!!"

    don't forget the "water loss" excuse.... ;-)

    [sigh] i DO get SO tired of the "fucking liar" excuse in those papers! they're so convinced that the paradox exists -- if low-carbers lose more, they're under-reporting but if high-carbers gain, it's underestimation of how much they're eating.... if they're only going to throw out the results they so expensively gained, why don't they make everyone measure everything, and -- oh, yeah -- put a GPS on 'em, so they can't sneak into gyms, too!

  3. Then there is this piece of evidence that is particularly damning to the idea that it makes any difference what your carb to fat ratio is as far as energy expenditure goes. It seems protein is the only macro that has a significant effect on energy expenditure.

    I don't believe a calorie is a calorie because protein proves that's not the case, but why does it appear that way with fat and carbs in tightly controlled studies?

  4. Dave actually one of the things I wanted to convery in this post is that energy expenditure does not mean much at all for adiposity. Things like height ( which is positively correlated with energy expenditure ) and basal metabolic rate do not predict adiposity.

  5. Not sure I follow you. What predicts adiposity? Its already well known that you cannot rely on dieters to properly report their calorie intake so I wouldn't take any study that is designed that way too seriously. It does seem the more controlled a study is, the more the advantage of low-carb disappears and becomes all about the protein intake.

  6. Actually are you implying that we cannot account for the changes in adiposity even when measuring both calorie intake and energy expenditure? I think I now understand what you mean when you say BMR doesn't predict energy expenditure, and I agree but I'm not saying it does either. I think its predicted by how your appetite compares to your expenditure. And I think the key to this is managing appetite to reduce calorie intake enough to be in a caloric deficit or maintain a balance, but I don't think energy expenditure is going to change for the better in the average person by choosing low carb.