boris
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Calorie for calorie, dietary fat restriction results in more body fat loss than carbohydrate restriction in people with obesity
Calorie for calorie, dietary fat restriction results in more body fat loss than carbohydrate restriction in people with obesity
Summary
Dietary carbohydrate restriction has been purported to cause endocrine adaptations that promote body fat loss more than dietary fat restriction. We selectively 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 isocaloric 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/d of body fat, fat oxidation was unchanged by fat restriction leading to 89±6 g/d of fat loss and was significantly greater than carbohydrate restriction (p=0.002). Mathematical model simulations agreed with these data, but predicted that the body acts to minimize body fat differences with isocaloric diets varying in carbohydrate and fat.
Introduction
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Therefore, outpatient studies cannot determine to what extent any observed differences in weight loss are due to a metabolic advantage of reduced carbohydrate diets versus a greater reduction in overall energy intake.
We performed an in-patient metabolic balance study examining the effect of selective isocaloric reduction of dietary carbohydrate versus fat on body weight, energy expenditure, and fat balance in obese volunteers. A mechanistic mathematical model of human macronutrient metabolism (Hall, 2010) was used to design the study and predict the metabolic response to each diet before the study was conducted (Hall, 2012). Here, we report the results of this experiment and use the mathematical model to quantitatively integrate the data and make in silico predictions about the results of long-term diet studies that are not practical to perform in the real world. In agreement with our model simulations, we found that only the reduced carbohydrate diet led to significant changes in metabolic fuel selection, with sustained reductions of carbohydrate oxidation and increased fat oxidation. Remarkably, fat oxidation on the reduced fat diet remained unchanged and resulted in a greater rate of body fat loss compared to the reduced carbohydrate diet, despite being equivalent in calories.
...
Discussion
This study demonstrated that, calorie for calorie, restriction of dietary fat led to greater body fat loss than restriction of dietary carbohydrate in adults with obesity. This occurred despite the fact that only the carbohydrate restricted diet led to decreased insulin secretion and a substantial sustained increase in net fat oxidation compared to the baseline energy-balanced diet.
In contrast to previous claims about a metabolic advantage of carbohydrate restriction for enhancing body fat loss (Ludwig and Friedman, 2014; Taubes, 2007, 2011; Westman et al., 2007), our data and model simulations support the opposite conclusion when comparing the RF and RC diets. Furthermore, we can definitively reject the claim that carbohydrate restriction is required for body fat loss (Taubes, 2011).
...
In summary, we found that selective reduction of dietary carbohydrate resulted in decreased insulin secretion, increased fat oxidation, and increased body fat loss compared to a eucaloric baseline diet. In contrast, selective isocaloric reduction of dietary fat led to no significant changes in insulin secretion or fat oxidation compared to the eucaloric baseline diet, but significantly more body fat was lost than during the carbohydrate restricted diet.
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I thought this was pretty interesting confirming what I read and heard from Peat, haidut and in the forum in general.
Anybody has more information on how this excretion of fat works? Peat says it get's excreted through the urine and I read in the forum that "glucuronidation" is the process, but all that I can find on google is useless.
Actually I stumbled upon the study when I was looking for this study with the obese women in the closed off ward that Peat talked about in this interview after the 5:53 mark.
Anybody know how to find it?
Calorie for calorie, dietary fat restriction results in more body fat loss than carbohydrate restriction in people with obesity
Summary
Dietary carbohydrate restriction has been purported to cause endocrine adaptations that promote body fat loss more than dietary fat restriction. We selectively 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 isocaloric 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/d of body fat, fat oxidation was unchanged by fat restriction leading to 89±6 g/d of fat loss and was significantly greater than carbohydrate restriction (p=0.002). Mathematical model simulations agreed with these data, but predicted that the body acts to minimize body fat differences with isocaloric diets varying in carbohydrate and fat.
Introduction
...
Therefore, outpatient studies cannot determine to what extent any observed differences in weight loss are due to a metabolic advantage of reduced carbohydrate diets versus a greater reduction in overall energy intake.
We performed an in-patient metabolic balance study examining the effect of selective isocaloric reduction of dietary carbohydrate versus fat on body weight, energy expenditure, and fat balance in obese volunteers. A mechanistic mathematical model of human macronutrient metabolism (Hall, 2010) was used to design the study and predict the metabolic response to each diet before the study was conducted (Hall, 2012). Here, we report the results of this experiment and use the mathematical model to quantitatively integrate the data and make in silico predictions about the results of long-term diet studies that are not practical to perform in the real world. In agreement with our model simulations, we found that only the reduced carbohydrate diet led to significant changes in metabolic fuel selection, with sustained reductions of carbohydrate oxidation and increased fat oxidation. Remarkably, fat oxidation on the reduced fat diet remained unchanged and resulted in a greater rate of body fat loss compared to the reduced carbohydrate diet, despite being equivalent in calories.
...
Discussion
This study demonstrated that, calorie for calorie, restriction of dietary fat led to greater body fat loss than restriction of dietary carbohydrate in adults with obesity. This occurred despite the fact that only the carbohydrate restricted diet led to decreased insulin secretion and a substantial sustained increase in net fat oxidation compared to the baseline energy-balanced diet.
In contrast to previous claims about a metabolic advantage of carbohydrate restriction for enhancing body fat loss (Ludwig and Friedman, 2014; Taubes, 2007, 2011; Westman et al., 2007), our data and model simulations support the opposite conclusion when comparing the RF and RC diets. Furthermore, we can definitively reject the claim that carbohydrate restriction is required for body fat loss (Taubes, 2011).
...
In summary, we found that selective reduction of dietary carbohydrate resulted in decreased insulin secretion, increased fat oxidation, and increased body fat loss compared to a eucaloric baseline diet. In contrast, selective isocaloric reduction of dietary fat led to no significant changes in insulin secretion or fat oxidation compared to the eucaloric baseline diet, but significantly more body fat was lost than during the carbohydrate restricted diet.
----
I thought this was pretty interesting confirming what I read and heard from Peat, haidut and in the forum in general.
Anybody has more information on how this excretion of fat works? Peat says it get's excreted through the urine and I read in the forum that "glucuronidation" is the process, but all that I can find on google is useless.
Actually I stumbled upon the study when I was looking for this study with the obese women in the closed off ward that Peat talked about in this interview after the 5:53 mark.
Anybody know how to find it?
