Lyle McDonald Article: Is a Calorie a Calorie?

[Nicholars]

"Summing up this mini-section: for the most part, studies where protein is adequate (or at least close to it), varying carbs and fats within the context of an identical caloric intake tends to have a minimal overall effect. (on fat loss / gain) "

I havnt read all of this thread but is that not a bit of an over simplified statement...

For example if you eat 3000 calories and it is all stored as fat or if you eat 3000 calories and some is stored as liver and muscle glycogen? In that case a calorie is not a "simple in out equation"?

Also the thermic effects of food?

[ATZ]

I'm not sure I understand your point Nic?

Also, thermic effect of food just adds to the "calorie out" side if things, and in the heirachy of thermic effects it's protein > carbs > fat.

[Nicholars]

Ok well forget about the thermic effect then but what I meant is for example if you were to eat 3000kcal of carbs either in a completely glycogen depleted state or with completely full glycogen then that 3000kcal of carbs would most likely either go to glycogen storage or fat storage....

SO if you manipulate your macro intakes etc. then you will likely gain less fat and more will go to the right places...

[ATZ]

Again you're using a strawman. That's not the main thrust of the argument here. The arguments is, that protein being sufficient, manipulating carbs or fat makes little differnce to fat loss or gain where diets are isocalorifically matched (same calories).

You can't refer to specific situations where you're completely glycogen depleted then eating 3000kcal of carbs verses being in a situation where you're eating 3000kcal extra of carbs on top of a normal diet.

The point here, is within a mixed bodybuilding diet, once protein targets are met maipulation of other macros makes no difference to bodycomposition outside of personal preference, adhering to the diet, activity levels etc. Some prefer more carbs, some more fat. End of. A calorie is still a calorie.

[Loki]

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Please keep these studies coming - it saves me having to find studies that support the 'calorie is NOT a calorie' hypothesis!

Let's see. Total weight lost on the VLCHF diet was 11.9 ± 6.3 kg, so the range was 12.6 kg with the lowest weight loss at 5.6kg and the highest at 18.2 kg. Total weight lost on the HCLF diet was 10.1 ± 5.7 kg, so the the range was 11.4kg with the lowest weight loss at 4.4 kg and the highest at 15.8 kg. So between the subject(s) with the highest degree of weight loss on both diets, there is a difference of 2.4 kg (or 5.28 lbs). That may not be statistically significant but it would be significant to a real-world dieter who wanted to lose a few extra pounds without having to cut calories even further on a HCLF diet!


As above - no statistically different weight loss but there was a bigger weight loss in the low carb group despite the authors' caveat:




Yet again, we see the absolute weight loss was better with the low carb diet even though not statistically significant. Real-world dieters are more interested in actual real-world results (more weight lost without need to further limit calories) than they are in statistics. Even when the weight loss evened out between the two diets at 12 months there is almost double the amount of actual weight lost (on average) in the low carb group. There were more drop-outs among the subjects on the traditional diet - again, in the real world - people want a diet that is easy and comfortable to stick to for long periods.

In the first two studies it is shown that health markers are significantly improved on the low carb diet, irrespective of weight loss another bonus for people wanting to improve the diet.

Next!

Total weight loss is not the same as fat loss and on a glance none of the studies here distinguish between the two. With that consideration in mind such things can't be used as justification that Low Carb Diets are better for fat loss, especially since low cab diets also result in a lesser state of hydration which could easily account for the statistically unsignificant slight increase in total weight loss with the LC diets.

This study does measure body comp change as well as total fat loss and the difference between groups after one year does slightly favour the low carb diet:

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Both groups lost similar amounts of weight (LC: –14.5 ± 1.7 kg; LF: –11.5 ± 1.2 kg; P = 0.14, time x diet) and body fat (LC: –11.3 ± 1.5 kg; LF: –9.4 ± 1.2 kg; P = 0.30)

Long-term effects of a very-low-carbohydrate weight loss diet compared with an isocaloric low-fat diet after 12 mo -- Brinkworth et al. 90 (1): 23 -- American Journal of Clinical Nutrition

But in comparing the differences between total weight loss and bodyfat loss for both conditions it works out that the LC group lost 3.2 ± 0.2 kg non fat weight whilst the LF group lost 2.1 ± 0 kg non fat weight.

Calculated as a proportion of total weight loss within each group, this makes the percentage of the weight loss from the LC group from non fat weight higher than in the LF group - the low carb group lost less fat as a total percentage of weight lost, even though the total fat loss slightly favoured the LC group.

If true of this dietary study, I don't see why similar proportions would not transfer to other studies too.

...

However, in " is a calorie a calorie" debates it's just as important to look at what happens in over feeding as in under feeding. I would like to see the full study for this because it's conclusions suggest a significant difference in what happens to excess calories between high fat and high carb diets:

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Fat and carbohydrate overfeeding in humans: different effects on energy storage

TJ Horton, H Drougas, A Brachey, GW Reed, JC Peters and JO Hill
Center for Human Nutrition, University of Colorado Health Sciences Center, Denver 80262, USA.

Both the amount and composition of food eaten influence body-weight regulation. The purpose of this study was to determine whether and by what mechanism excess dietary fat leads to greater fat accumulation than does excess dietary carbohydrate. We overfed isoenergetic amounts (50% above energy requirements) of fat and carbohydrate (for 14 d each) to nine lean and seven obese men. A whole-room calorimeter was used to measure energy expenditure and nutrient oxidation on days 0, 1, 7, and 14 of each overfeeding period. From energy and nutrient balances (intake-expenditure) we estimated the amount and composition of energy stored. Carbohydrate overfeeding produced progressive increases in carbohydrate oxidation and total energy expenditure resulting in 75-85% of excess energy being stored. Alternatively, fat overfeeding had minimal effects on fat oxidation and total energy expenditure, leading to storage of 90-95% of excess energy. Excess dietary fat leads to greater fat accumulation than does excess dietary carbohydrate, and the difference was greatest early in the overfeeding period.

Fat and carbohydrate overfeeding in humans: different effects on energy storage -- Horton et al. 62 (1): 19 -- American Journal of Clinical Nutrition

This is interesting also -

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Failure of dietary fat intake to promote fat oxidation: a factor favoring the development of obesity

Y Schutz, JP Flatt and E Jequier
Institute of Physiology, Faculty of Medicine, University of Lausanne, Switzerland.

Seven young men spent three nights and 2 d in a respiration chamber where their rates of energy expenditure and substrate oxidation were continuously measured by indirect calorimetry. During the first 24 h they ingested a mixed maintenance diet containing 35% of calories as fat. An additional amount of 106 +/- 6 g fat/24 h (means +/- SD) was added to this diet during the following 36 h. The fat supplement (987 +/- 55 kcal/d) did not alter 24-h energy expenditure (2783 +/- 232 vs 2820 +/- 284 kcal/d) and failed to promote the use of fat as a metabolic fuel (fat oxidation 1032 +/- 205 vs 1042 +/- 205 kcal/d). The overall energy balance was closely correlated with the fat balance (r = 0.96, p less than 0.001) but not with the carbohydrate balance (r = - 0.12, NS). These data indicate that substantial imbalances between intake and oxidation are much more likely for fat than for carbohydrate.

Failure of dietary fat intake to promote fat oxidation: a factor favoring the development of obesity -- Schutz et al. 50 (2): 307 -- American Journal of Clinical Nutrition

And:

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Substrate utilization in man: Effects of dietary fat and carbohydrate
Wilhelmine P.H.G. Verboeket-van de VenneCorresponding Author Contact Information, a, Klaas R. Westerterpa and Foppe ten Hoora

aDepartment of Human Biology, University of Limburg, Maastricht, The Netherlands.
Received 10 August 1992;
accepted 19 April 1993.
Available online 6 April 2004.

Abstract

In man there is evidence that the ability to adjust fat oxidation to fat intake is less effective than the ability to adjust carbohydrate and protein oxidation to carbohydrate and protein intake. The short-term (3-day) effects of a low-fat (LF), mixed (M), and high-fat (HF) diet on human substrate balances were studied using a respiration chamber. Subjects were 14 young female students classified by means of their scores on psychometric questionnaires as “restrained” or “unrestrained” eaters. Subjects were in energy balance, ie, the mean difference between energy intake (EI) and energy expenditure (EE) was 86 ± 85 kJ/d. The fat content of the food significantly influenced the 24-hour respiratory quotient (RQ) and nonprotein respiratory quotient (NPRQ). For both the LF and M diets, the 24-hour RQ was significantly lower than the food quotient (FQ), whereas the RQ on the HF diet was not different from the FQ. Oxidation of fat and carbohydrate significantly increased with, respectively, an increasing fat and carbohydrate content of the diet for both restrained- and unrestrained-eating subjects. Restrained-eating subjects showed a decreased fat oxidation compared with unrestrained eaters in response to a HF diet, resulting in a positive fat balance for restrained-eating subjects. On a LF diet, fat balance was negative for both groups of subjects, indicating net endogenous fat oxidation. In conclusion, restrained-eating subjects have more difficulty in the handling of a HF diet, possibly explaining their higher susceptibility to becoming obese.

ScienceDirect - Metabolism : Substrate utilization in man: Effects of dietary fat and carbohydrate

The three abstracts when compared to the number crunching from the weight loss diets (and many others I've looked at) suggest to me that a calorie isn't a calorie, but that high fat low carb gives a very slight advantage in calorie restricted conditions but also a slight detriment in over feeding conditions.

I'd also conclude that any metabolic advantage is A LOT smaller than is often touted, and based on experience of trying numerous macro ratios in my own diet that the biggest advantage from low carb eating is plain and simple appetite suppression coming from higher protein levels... although high fibre carb diets also can have this effect.

[NU_nutrition_TS]

The weakness I see with that last but one study (and most others of the same ilk) was that the overfeeding of fat was merely additional to a mixed diet which already had a significant dose of carbohydrates. Due to the substrate oxidation hierarchy, carbohydrate will always take precedence over, and interfere with, the oxidation of fat. This is why a high fat diet MUST be low carb - preferably <50g per day.

EDIT: Also, what type of fat was fed? Long-chain polyunsaturated fatty acids don't upregulate fatty acid oxidation as much as short and medium chain saturated fatty acids.

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In order to examine the effect of dietary long chain fatty acid composition on energy substrate utilization, basal metabolism rate (BMR) and the thermogenic effect of food (TEF) were measured in eight subjects consuming diets varying only in diet fat polyunsaturated: saturated (P:S) ratio. Subjects consumed the low P:S (0.241 ± 0.02) and high P:S (1.65 ± 0.28) ratio diets for seven days using a crossover design. Fat and carbohydrate oxidation during BMT and TEF over 230 minutes after a breakfast meal were determined on days 1 and 7 of each diet period using open circuit respiratory gas exchange. On day 7, BMR respiratory quotient was reduced (P < .05) for the low P:S (0.826 ± 0.005) compared with high P:S (0.853 ± 0.014) ratio diet, resulting in an increased basal fat oxidation rate with low P:S (0.074 ± 0.006 g/min) compared with high P:S (0.059 ± 0.008 g/min) ratio diet feeding.

http://www.sciencedirect.com/science...b082163fe9e12a

Unfortunately, most of these studies do not differentiate between weight loss/gain and fat loss/gain. Lean mass loss is likely on any diet, including a mixed calorie-restricted diet. The only way to minimise lean mass loss (particularly muscle tissue) is to incorporate resistance exercise. When there appears to be greater lean mass loss in high fat/restricted carb diets, how much of this is due to glycogen/water depletion within muscle tissue and how much is actually due to a loss of functional muscle tissue?

However, I concur with your conclusion that a calorie is NOT just a calorie!

[Loki]

I think all this proves that there is that all the studies cited are unable to paint an entire picture of the effect of different macros on metabolism - so far, no study methodology has led to either absolute conclusive support for a view point or absolute rejection of the other.

In each study analysed each of us has included a degree of speculation in interpreting the data, and however fair we seek to be, we do each approach it from a point of view of sympathy to a particular theory.

I do not believe all calories are equal all the time, however also do not believe there is very much significance at all in the difference.

Is a very interesting discussion though, and great points raised by everyone throughout this thread which I've enjoyed reading.

[hailtotheking]

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I do not believe all calories are equal all the time, however also do not believe there is very much significance at all in the difference.

I think that sums it up nicely.

[Gareth83]

this of course when your talking in terms of calories as energy

I'd rather my calories come from nutrition dense foods which always seem to come from animal products ie. protein/fat

[NU_nutrition_TS]

Sean Croxton of Underground Wellness admits he got it wrong about calories just being calories!

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