Math, Obesity & You: Is a Calorie Still a Calorie?

A place to get your questions answered from McDougall staff dietitian, Jeff Novick, MS, RDN.

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Re: Math, Obesity & You: Is a Calorie Still a Calorie?

Postby JeffN » Thu Feb 14, 2019 7:48 am

A two year study

Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates
February 26, 2009
N Engl J Med 2009; 360:859-873
DOI: 10.1056/NEJMoa0804748

https://www.nejm.org/doi/full/10.1056/NEJMoa0804748

Abstract

BACKGROUND
The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year.

METHODS
We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content.

RESULTS
At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels.

CONCLUSIONS
Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize. (ClinicalTrials.gov number, NCT00072995.)



CSPI Article on the last 2 studies posted here

Cutting carbs, fat, or protein for weight loss
When you’re trying to lose weight, what matters more: cutting fat, cutting protein, or cutting carbs?
POSTED ON FEBRUARY 11, 2019 BY NAH EDITORIAL STAFF

https://www.nutritionaction.com/daily/h ... ight-loss/
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Re: Math, Obesity & You: Is a Calorie Still a Calorie?

Postby JeffN » Tue Apr 30, 2019 10:24 am

Defending Thermodynamics in a Diet Debate
April 29, 2019• Physics 12, 47

“Experiments show that calories from different food types are equivalent and that the laws of thermodynamics apply to human metabolism, despite claims to the contrary.

https://physics.aps.org/articles/v12/47

“A calorie is of course a calorie,” says Kevin Hall, who trained as a physicist and currently conducts experiments and develops mathematical models for metabolism and body weight regulation at the National Institutes of Health in Maryland. Hall agrees that different macronutrients—think fats versus carbohydrates—have very different effects on the body, but he strongly disagrees with Preece’s claim. If the question is just about the number of calories burned by the body, rather than stored as fat, it’s “practically the same” for two foods having the same calorie rating, regardless of their fat or carb content, he says.

In experiments where people are fed meals with identical numbers of calories but different carb and fat contents, results show that the body burns nearly the same amount of energy. The models predict the same outcome. “We’re talking about differences on the order of [just] tens of calories a day in people whose diet is tightly controlled,” Hall says. “We can pretty confidently say there doesn’t seem to be much effect.” Of course, carbs and fats affect the body differently in many other ways, such as with their power to satiate, but their impacts on body fat per calorie are essentially the same.”
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Re: Math, Obesity & You: Is a Calorie Still a Calorie?

Postby JeffN » Sat Jul 27, 2019 6:26 am

Calories Made Combustibly Simple
David L. Katz, MD, MPH

https://www.linkedin.com/pulse/calories ... mple-david

"The recently published CALERIE trial should sound the death knell of every fad diet that ever was, is, or would be (it won't, of course). The study showed, in the proverbial nutshell, that calorie restriction, per se, causes weight loss in the overweight, which in turn causes an array of improvements in the customary measures of cardiometabolic risk."
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Re: Math, Obesity & You: Is a Calorie Still a Calorie?

Postby JeffN » Sat Sep 07, 2019 7:22 am

JeffN wrote:Too short term for me (only 6 days on each diet) as there are more metabolic adaptions that happen over time, but you don’t get better controlled then this...

"confined to a metabolic ward where they exercised daily.” :)

In Health
Jeff


Cell Metabolism: Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity
Kevin Hall, et al.,
Cell Metabolism 22, 1–10, September 1, 2015
DOI: http://dx.doi.org/10.1016/j.cmet.2015.07.021

http://www.cell.com/cell-metabolism/ful ... 50-4131(15)00350-2

SUMMARY

Dietary carbohydrate restriction has been purported to cause endocrine adaptations that promote body fat loss more than dietary fat restriction. We selec- tively restricted dietary carbohydrate versus fat for 6 days following a 5-day baseline diet in 19 adults with obesity confined to a metabolic ward where they exercised daily. Subjects received both isoca- loric diets in random order during each of two inpatient stays. Body fat loss was calculated as the difference between daily fat intake and net fat oxidation measured while residing in a metabolic chamber. Whereas carbohydrate restriction led to sustained increases in fat oxidation and loss of 53 ± 6 g/day of body fat, fat oxidation was un- changed by fat restriction, leading to 89 ± 6 g/day of fat loss, and was significantly greater than carbo- hydrate restriction (p = 0.002). Mathematical model simulations agreed with these data, but predicted that the body acts to minimize body fat differences with prolonged isocaloric diets varying in carbohydrate and fat.

Highlights

- 19 adults with obesity were confined to a metabolic ward for two 2-week periods

- Cutting carbohydrates increased net fat oxidation, but cutting fat by equal calories had no effect

- Cutting fat resulted in more body fat loss as measured by metabolic balance

- Mathematical model simulations predicted small long-term differences in body fat

Image
'

This past week, Dr Greger did a video about this study. Kevin Hall, principle investigator of the study, then responded to Dr Greger's video.

https://mobile.twitter.com/KevinH_PhD/s ... et%3DTweet

In Health
Jeff
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Re: Math, Obesity & You: Is a Calorie Still a Calorie?

Postby JeffN » Sat Sep 04, 2021 10:51 am

"Calories in, calories out" and macronutrient intake: the hope, hype, and science of calories.
Am J Physiol Endocrinol Metab. 2017 Nov 1;313(5):E608-E612. doi: 10.1152/ajpendo.00156.2017. Epub 2017 Aug 1.
PMID: 28765272

https://journals.physiology.org/doi/ful ... 00156.2017

Abstract

One of the central tenets in obesity prevention and management is caloric restriction. This perspective presents salient features of how calories and energy balance matter, also called the "calories in, calories out" paradigm. Determinants of energy balance and relationships to dietary macronutrient content are reviewed. The rationale and features of the carbohydrate-insulin hypothesis postulate that carbohydrate restriction confers a metabolic advantage. According to this model, a large amount of fat intake is enabled without weight gain. Evidence concerning this possibility is detailed. The relationship and application of the laws of thermodynamics are then clarified with current primary research. Strong data indicate that energy balance is not materially changed during isocaloric substitution of dietary fats for carbohydrates. Results from a number of sources refute both the theory and effectiveness of the carbohydrate-insulin hypothesis. Instead, risk for obesity is primarily determined by total calorie intake.

Conclusion

The CHO-insulin hypothesis predicted that lowering dietary CHO significantly should cause insulin levels to fall, leading to release of fat from adipocytes that would 1) increase fat loss and 2) increase EE to claimed amounts in the range of ≥350 cal/day (range 400–600). Neither of these effects was observed in two current and highly rigorous metabolic ward studies, one of which was the actual NuSI study being discussed.

Weight gain or loss is not primarily determined by varying proportions of CHO and fat in the diet, but instead by the number of calories ingested. Changes in EE, which metabolic pathways are used and other considerations are quite modest when compared with caloric intake. Until high-quality, metabolic ward primary data become available indicating otherwise, a calorie is still a calorie.
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