Carbohydrates can be stores as body fat thru de novo lipogenesis, but it takes a lot >500 grams of carbohydrates a day. With carbohydrates overfeeding, there is an increase in energy expenditure, but this does not seem to occur with fat overfeeding. Once glycogen stores are full, de novo lipogenesis (i.e., creation of fat from carbohydrates) starts to occur.



  • Carbs turn into fat, but it takes a lot!!
  • When an excess of 500 grams of carbohydrates was eaten per day, carbohydrates were converted to fat. (That is a lot of pasta!)
  • Once glycogen stores are full, de novo lipogenesis (i.e., creation of fat from carbohydrates) starts to occur.


Popular diets have advocated cutting your complex carb intake to lose weight. Popular diets such as the Zone Diet advocate increasing fat intake and limiting carbs as a source of energy. The specific macros are 40% protein, 30% carbs, 30% fat. The problem with this diet is that it limits the good carbs for bodybuilders to train intensely to gain muscle.

Fat vs. carbs for energy is not a factor if your workouts are less than 45 minutes. If you train for over an hour or train with multiple sessions per day, then low carbs may limit muscle gain. Do carbs help build muscle mass/are carbs good for muscle gain is a common question?

Eating carbohydrates such as sweet potatoes, brown rice, and simple carbohydrates are being touted as the cause of weight gain. Carbs increase blood glucose levels, and spike insulin, causes obesity, is still being spread on the information despite it being a myth!

The biochemical process in which excess carbohydrates are converted into body fat is known as de novo lipogenesis. It takes a lot of carbohydrates for this process to occur!! Do carbs cause fat? Yes, but only when consumed in excess!

The studies that are mentioned below all have one thing in common. If you give people a caloric surplus of carbohydrates or fats, an increase in fat gain can occur.

Obesity is due to excess calories! Carbs turn into fat when consumed in excess. Fat turns into fat when consumed in excess.


This should be distinct from someone eating within their caloric balance. Many ask, “Should I cut fat or carbs?” You can cut either one and lose body fat.


Here are commonly asked questions and answers regarding fat and carbs for fat loss:

  • Q: Is eating fat better than carbs?
  • A: Cutting fat vs. carbs weight loss is similar when diets are standardized. You can cut either carbs or fat and lose fat. Long-term studies have shown that when protein and calories are standardized between groups, there is no difference in fat loss between the high-carbs, low-fat foods group and the low-carb, high-fat foods group. You can consume high carbs and low-fat meals and lose weight equally effectively as a low-carb, high-fat meals when diets are similar.
  • Q: Is it better to go over in fat or carbs?
  • A: As you will read below, storing fat from excess carbs is much more energetically difficult than overconsumption of fat.
  • Q: Do carbs make you fat or calories?
  • A: As long as you are in a calorie deficit, carbs will not make you fat. Popular diets, such as the potato and rice diet, advocate high carbohydrates, yet weight loss still occurs. Obesity is the result of excess calorie consumption rather than carbs.


Studies have shown that you can eat a diet with 50% carbohydrates and lose weight, and de novo lipogenesis will decrease if you eat in a caloric deficit.(1) It takes a very large surplus of carbohydrates to be converted to body fat. Excess carbohydrates can stimulate key lipogenic enzymes in adipose tissue.

In one study, 500 grams of carbohydrates were fed to subjects, such as bread, jam, and fruit juice. Note: 11 cups of white rice is about 495 grams of carbohydrates to give you an idea of how many carbohydrates they were eating. Even after this massive feeding of carbohydrates, there was no net gain in body fat; it was stored as glycogen. These subjects were not glycogen-depleted either, so excessive carbohydrates are not easily converted to body fat acutely.(2)


In studies, researchers increased the intake of excess calories from carbohydrates above the baseline, leading to an increase in baseline energy expenditure. However, overfeeding fat didn’t result in any increase in energy expenditure(3, 4) Carbohydrate overfeeding boosted NEAT, but fat overfeeding didn’t elevate any energy expenditure parameter.

Therefore, when consuming excess calories, the body stores overfed fat more readily as body fat, while it’s less likely to store excess carbohydrates. In a different study, participants adopted a low-carb diet and exercise routine to deplete their glycogen stores. After that, researchers put them on a diet with a significant carbohydrate surplus to identify when excess carbohydrates turn into body fat.

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For seven days, the subjects consumed excess carbohydrates (i.e., carbohydrates increased from 836 grams to 1036 grams). Once glycogen stores became saturated at 500 grams, de novo lipogenesis began, resulting in a 142-gram net fat gain each day. The seven-day overfeeding of carbohydrates led to a 1.1 kg or a .5 lb. pound fat gain.(5)

The author concluded that when glycogen stores are full, eating 500 grams of carbohydrates daily results in de novo lipogenesis, and carbs are converted to body fat. So yes, carbohydrates can be converted to body fat, but it takes a lot!!

Other studies have found that overfeeding with fructose (i.e., 25% caloric surplus) and sucrose or table sugar (i.e., 50% overfeeding) results in de novo lipogenesis as well.(6, 7) One should realize that despite the massive carbohydrate overfeeding, the contribution to fat gain was relatively small.

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700 grams of carbohydrate overfeeding (175 % of energy requirement) increased net de novo lipogenesis at the expense of glycogen synthesis. An increase in mRNAs coding for key lipogenic enzymes suggests that de novo lipogenesis occurred, at least in part, in adipose tissue.

In sum, de novo lipogenesis, or converting carbs to body fat, is not a major driver of gaining body fat if you eat within caloric balance. Despite some people saying you can’t lose weight on high-carbohydrate diets, several studies show that a high-carb/low-fat/high-fiber diet can enhance weight loss.

One study investigated the impact of three diets:

  • A control diet
  • A high-carbohydrate diet fiber-rich diet
  • A high-carbohydrate diet with aerobic exercise

The subjects in the high carbohydrate and high carbohydrate plus exercise groups ate as many carbohydrates as they felt they wanted; there were no restrictions.


At the end of the study, both the high carbohydrate and high carbohydrate groups plus exercise lost weight compared to the control group.(10) This is different from saying that you can eat as many carbs as you want. Any excess calories can convert to body fat from excess carbohydrates or fats. In today’s society, high carbohydrate diets are getting all the blame for obesity.

A recent meta-analysis discovered that whole grain consumption did not lead to an increase in obesity.(11) The body converts carbs into fat, but this process requires a large amount of carbohydrates. We need to dispel the misconception that carbs are easily stored as body fat.


    • Carbohydrates can be a storage as body fat thru de novo lipogenesis, but it takes a lot!
    • With carbohydrate overfeeding, there is an increase in energy expenditure, but this does not seem to occur with fat overfeeding.


1.         Schwarz JM, Neese RA, Turner S, Dare D, Hellerstein MK. Short-term alterations in carbohydrate energy intake in humans. Striking effects on hepatic glucose production, de novo lipogenesis, lipolysis, and whole-body fuel selection. J Clin Invest. 1995;96(6):2735-43.

2.         Acheson KJ, Flatt JP, Jéquier E. Glycogen synthesis versus lipogenesis after a 500 gram carbohydrate meal in man. Metabolism. 1982;31(12):1234-40.

3.         Marques-Lopes I, Ansorena D, Astiasaran I, Forga L, Martínez JA. Postprandial de novo lipogenesis and metabolic changes induced by a high-carbohydrate, low-fat meal in lean and overweight men. Am J Clin Nutr. 2001;73(2):253-61.

4.         Dirlewanger M, Vetta Vd, Guenat E, Battilana P, Seematter G, Schneiter P, et al. Effects of short-term carbohydrate or fat overfeeding on energy expenditure and plasma leptin concentrations in healthy female subjects. International Journal of Obesity. 2000;24(11):1413-8.

5.         Acheson KJ, Schutz Y, Bessard T, Anantharaman K, Flatt JP, Jéquier E. Glycogen storage capacity and de novo lipogenesis during massive carbohydrate overfeeding in man. Am J Clin Nutr. 1988;48(2):240-7.

6.         Faeh D, Minehira K, Schwarz J-M, Periasamy R, Park S, Tappy L. Effect of Fructose Overfeeding and Fish Oil Administration on Hepatic De Novo Lipogenesis and Insulin Sensitivity in Healthy Men. Diabetes. 2005;54(7):1907-13.

7.         McDevitt RM, Bott SJ, Harding M, Coward WA, Bluck LJ, Prentice AM. De novo lipogenesis during controlled overfeeding with sucrose or glucose in lean and obese women. The American Journal of Clinical Nutrition. 2001;74(6):737-46.


8.         Solinas G, Borén J, Dulloo AG. De novo lipogenesis in metabolic homeostasis: More friend than foe? Mol Metab. 2015;4(5):367-77.

9.         Lammert O, Grunnet N, Faber P, Bjørnsbo KS, Dich J, Larsen LO, et al. Effects of isoenergetic overfeeding of either carbohydrate or fat in young men. Br J Nutr. 2000;84(2):233-45.

10.       Hays NP, Starling RD, Liu X, Sullivan DH, Trappe TA, Fluckey JD, et al. 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. Arch Intern Med. 2004;164(2):210-7.

11.       Sadeghi O, Sadeghian M, Rahmani S, Maleki V, Larijani B, Esmaillzadeh A. Whole-Grain Consumption Does Not Affect Obesity Measures: An Updated Systematic Review and Meta-analysis of Randomized Clinical Trials. Advances in Nutrition. 2019;11(2):280-92.

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