Study: High-Carb Diet Results In More Weight Loss And Fat Loss


Participants who ate an unlimited amount of food from a high-carbohydrate diet lost more weight and more body fat than those who ate more fat and fewer carbs. (Photo of our breakfast oatmeal with berries, banana, and cinnamon.)

Does eating carbohydrate make us fat? I don’t think it does. I think eating fat makes us fat.

What if you gave two groups of people more food than you think they could eat, one group’s food was high in carbohydrate and low in fat, the other group’s was lower in carb and higher in fat. They could eat as much as they wanted, no calorie counting, no limited servings. If carbohydrate makes us fat, you’d think the high-carb group would gain more body weight and more body fat.

Here’s that exact study. The high-carb group lost more body weight and body fat:

Effects Of An Ad Libitum Low-Fat, High-Carbohydrate Diet On Body Weight, Body Composition, And Fat Distribution In Older Men And Women: A Randomized Controlled Trial, Archives of Internal Medicine, January 2004

METHODS: We examined the effect of a 12-week low-fat, high-complex carbohydrate diet alone (HI-CHO) and in combination with aerobic exercise training (HI-CHO + EX) on body weight and composition in 34 individuals with impaired glucose tolerance (20 women and 14 men; mean +/- SEM age, 66 +/- 1 years). Participants were randomly assigned to a control diet (41% fat, 14% protein, 45% carbohydrates, and 7 g of fiber per 1000 kcal), a HI-CHO diet (18% fat, 19% protein, 63% carbohydrates, and 26 g of fiber per 1000 kcal), or a HI-CHO diet plus endurance exercise 4 d/wk, 45 min/d, at 80% peak oxygen consumption (HI-CHO + EX). Participants were provided 150% of estimated energy needs and were instructed to consume food ad libitum. Total food intake, body composition, resting metabolic rate, and substrate oxidation were measured.

RESULTS: There was no significant difference in total food intake among the 3 groups and no change in energy intake over time. The HI-CHO + EX and HI-CHO groups lost more body weight (-4.8 +/- 0.9 kg [P=.003] and -3.2 +/- 1.2 kg [P=.02]) and a higher percentage of body fat (-3.5% +/- 0.7% [P=.01] and -2.2% +/- 1.2% [P=.049]) than controls (-0.1 +/- 0.6 kg and 0.2% +/- 0.6%). In addition, thigh fat area decreased in the HI-CHO (P=.003) and HI-CHO + EX (P<.001) groups compared with controls. High carbohydrate intake and weight loss did not result in a decreased resting metabolic rate or reduced fat oxidation.

CONCLUSION: A high-carbohydrate diet consumed ad libitum, with no attempt at energy restriction or change in energy intake, results in losses of body weight and body fat in older men and women.

After 12 weeks, the high-carb group lost 7 pounds, 11 pounds if they exercised 4 days a week (on a cycle for 45 minutes). The higher-fat/lower-carb group lost 0.2 pounds, or 1/5th of a pound. For most of the study they actually put on a bit of weight. The high-carb group also lost more body fat:


The high-carb group was getting 18% of their calories from fat (food was provided). I’d call that a low-fat diet. Recall that the “low-fat” group in the PREDIMED study was getting 37% of their calories from fat. That is not a low-fat diet. That is a typical high-fat American diet, as is the diet of the control group in this study (which ate 41% fat).

Eating carbohydrate does not make us fat. Eating fat makes us fat:

It has been suggested that high-carbohydrate diets may contribute, over time, to excess body fat storage owing to reduced fat oxidation and increased de novo lipogenesis. In contrast, the results of the present study support the hypothesis that fat balance is maintained not by total energy intake but by total fat intake. Previous studies have clearly demonstrated that overconsumption of carbohydrates does not result in lipogenesis to any great extent.

Recently, low-carbohydrate diets have become popular for individuals attempting to lose weight. The proponents of these diets claim that because dietary carbohydrates stimulate insulin production, de novo lipogenesis results in positive fat balance. As described herein, however, little evidence exists to support this idea.

1 thought on “Study: High-Carb Diet Results In More Weight Loss And Fat Loss

  1. Bix Post author

    The thing about eating a high-carb, starch-rich diet is that you have to also eat low-fat. You can’t eat both high-carb and high-fat. I mean, you can, but you’ll watch your blood sugars go up and your waistline expand. You have to eat the bagel without the cream cheese, the pasta without the cream sauce, or without oily pesto. I know. And you have to cut way back on animal food, which is a good source for fat, especially saturated fat. This is why some vegetarians and vegans can still be eating a diet that isn’t healthful. They’re doubling up on the eggs, cheese, and oil.

    A high-carb, high-fat diet has come to be known as a “meat-and-potatoes” diet, even if it doesn’t include those foods:

    High-Fat High-Sugar Dietary Pattern (“Meat & Potatoes”) Linked To Colon Cancer, Diabetes

    “Meat And Potatoes” Dietary Pattern And Risk For Colon Cancer



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