This Is What Happens to Your Body When You Stop Eating Carbs


Half Baked Harvest 

Low-carb diets have been lauded as effective weight loss diets for years, According to a 2018 survey by the International Food Information Council Foundation, consumers rank sugar and carbs as the top reasons for weight gain—the highest ranking since 2011. So why, then, are stories emerging that low-carbohydrate diets are unsafe and should be avoided?

Research by professor Maciej Banac of the Medical University of Lodz, Poland, found that "people who consumed a low carbohydrate diet were at greater risk of premature death" with an increased risk of coronary heart disease, stroke, and cancer. More research from a separate study in Reader's Digest revealed that "low-carb dieters—people who got less than 40% of their daily calories from carbs—had a higher mortality risk during the study than did moderate carb consumers (whose diets are 50 to 55 percent carbs) and people who went carb crazy (more than 70 percent)."

Here's what actually happens to your body when you stop eating carbs.

Are low-carb diets healthy?
Half Baked Harvest

You May Experience the "Low-Carb" Flu

Juliana Shalek, MS, RD, CDN, and founder of The Nutrition Suite told MyDomaine that following a low-carb diet tends to promote weight loss at a relatively fast rate because cutting carbohydrates reduces blood glucose and insulin levels, which in turn minimizes fat storage in the body. However, Kristin Kirkpatrick, a dietitian at Cleveland Clinic, told Tonic that cutting carbs out altogether may result in fatigue, weakness, dizziness, headaches, irritability, and nausea that can last a few days or even weeks, also known as the "low-carb flu."

Your Body Will Eventually Go Into Ketosis

If you cut out carbs completely, your body will eventually go into a state of ketosis where "small fragments of carbon called ketones are released into the blood because the body is burning fat instead of carbohydrates." Keto diets might sound appealing at first, but fat is a slower source of fuel than glucose, which means it takes longer for your body to access it, so it will be harder to get going during exercise and other activities. 

Low-fiber diets can have a negative impact on both gastrointestinal and cardiovascular health.

You'll Lose Water Weight First

During a keto diet, you'll lose water weight first, which can be misleading, and then the non-water weight will follow. A 2013 meta-analysis published in the British Journal of Nutrition that compared low-carb ketogenic diets with traditional low-fat diets found that low-carb diets could be effective in reducing obesity rates. But when you consider the long-term health concerns mentioned earlier, cutting them out altogether doesn't seem like a healthy long-term option. 

Low-carb diet benefits
Half Baked Harvest

What About Going Low-Carb?

Celebrity nutritionist Kelly LeVeque told Chalkboard that we should also be looking at the "carbohydrate density" of our food rather than cutting them out altogether. Put simply, carb density means the percent of the food mass that is carbohydrate minus the fiber component. As LeVeque explains, most high-net carb foods will end up as sugar in your body. Whole foods in nature don't have a carb density over 30%; even carb-heavy vegetables will have a density well below that. It's processed foods that go well above that and as we all know, should be avoided.

Look for High Fiber Foods

The good news is, there are plenty of delicious high-fiber, low-carb foods you can eat that will keep you in shape and feeling good. Since fiber is neither digested nor absorbed, it actually takes up space in your intestine, giving you a feeling of fullness (and making it easier to minimize snacking and overeating). Registered dietician nutritionist Maya Feller, MS, RD, CDN, of Maya Feller Nutrition, says that the daily fiber recommendation for women is 25 grams (although women over 50 should aim for 21 grams instead). "Most Americans are not meeting their daily fiber needs," the expert told us. "Low-fiber diets can have a negative impact on both gastrointestinal and cardiovascular health."

low-carb diet
Half Baked Harvest

So in conclusion, do your research and eat healthy carbs that haven't been put through a refining process. Registered dietitian Nichola Whitehead defines these as whole grains, fruits, vegetables, proteins, and fats—you can eat low-carb foods on a vegetarian diet too.

Article Sources
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  1. European Society of Cardiology. Low Carbohydrate Diets are Unsafe and Should Be Avoided. August 28, 2018.

  2. Seidelmann S, Claggett B, Cheng S, Henglin M, Shah A, Steffen L., et al. Dietary Carbohydrate Intake and Mortality: A Prospective Cohort Study and Meta-Analysis. The Lancet. 2018 Sept; 3(9):E419-E428.doi:10.1016/S2468-2667(18)30135-X

  3. Bazzano LA, Hu T, Reynolds K, et al. Effects of Low-Carbohydrate and Low-Fat Diets: A Randomized Trial. Ann Intern Med. 2014;161(5):309-18.doi:10.7326/M14-0180

  4. Shilpa J, Mohan V. Ketogenic Diets: Boon or bane?. Indian J Med Res. 2018;148(3):251-253.doi:10.4103/ijmr.IJMR_1666_18

  5. Boison D. New Insights into the Mechanisms of the Ketogenic Diet. Curr Opin Neurol. 2017;30(2):187-192.doi:10.1097/WCO.0000000000000432

  6. Bueno NB, De melo IS, De oliveira SL, Da rocha ataide T. Very-Low-Carbohydrate Ketogenic Diet V. Low-Fat Diet for Long-Term Weight Loss: A Meta-Analysis of Randomised Controlled Trials. Br J Nutr. 2013;110(7):1178-87.doi:10.1017/S0007114513000548

  7. Spreadbury I. Comparison with Ancestral Diets Suggests Dense Acellular Carbohydrates Promote an Inflammatory Microbiota, and May Be the Primary Dietary Cause of Leptin Resistance and Obesity. Diabetes Metab Syndr Obes. 2012;5:175-89.doi:10.2147/DMSO.S33473

  8. USDA. Dietary Guidelines for Americans 2015-2020, Eighth edition.

  9. Tufts Nutrition. 10 Things You Need to Know About Fiber. Updated winter 2019.

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