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True or False? Low Carb Diets Are Good for You!

by | Last updated Jun 22, 2026 | Grains, Nutrition

You have seen it on Facebook, read it on the internet, heard it on the news: “Carbs are bad for you if you are trying to lose weight.” Pundits advocating a low-carbohydrate diet condemn the consumption of starches. They say that even whole grains sabotage your health. Consuming a high-protein diet assists in weight loss, but is it the best choice? Does the type of protein we eat make a difference in our desired goal to achieve health?

No doubt about it, consuming sugar, eating refined grains, and fried potatoes increases the risk for obesity, diabetes, liver damage, and a decline in kidney function. However, that is not the whole picture. True, regular consumption of simple carbohydrates such as sugar, high-fructose corn syrup, and desserts is detrimental.

The good carbs from whole grains, whole fruits, and whole vegetables are essential for brain health. As important as protein and healthful fats are, we still need to eat good carbs for optimal brain performance. Here is the evidence:

Low-Carb Diets Reduce Brain Function.

Low-carb diets reduce cognitive functioning. Glucose from carbohydrate is the brain’s preferred fuel. While the brain uses glucose as its primary fuel, it cannot store it.  Reducing carbohydrate intake reduces the brain’s primary source of energy.

Research at Tufts University shows that when dieters eliminate carbohydrates from their meals, they perform more poorly on memory-based tasks than when they reduce calories while maintaining carbohydrates. Researchers divided women into two groups. One group ate a low-calorie diet while the other consumed a low-carb diet. They took tests to measure their cognitive performance before and after their three-week diets.

Low-carb dieters showed a gradual decrease in memory-related tasks compared with the low-calorie dieters. Reaction time for those on the low-carb diet was slower. Their visuospatial memory was not as good as that of those on the low-calorie diet. 1 However, low-carb dieters responded better than the low-calorie dieters during the attention vigilance task.

How Much Carbohydrate Should We Eat?

The amount of carbohydrates depends on the type and the food sources of carbohydrates we eat!  A meta-analysis of 43, 000 people2 (after adjusting for age, sex, race, total energy intake, education, exercise, income level, smoking, and diabetes) found:

Both low and high-carb diets were linked with an increase in mortality. In contrast, consumers of a moderate amount of carbohydrates had the lowest mortality risk. Participants who ate a moderate amount of carbohydrates (40 to 60% of total calories) lived 4 years longer than those who ate a low-carb diet.  In addition, they lived one year longer than those who consumed a high-carb diet. In this study, a low-carbohydrate intake was defined as getting less than 40% of the total calories from carbohydrates.

Low-carb diets that replace carbohydrates with proteins and fats from plant sources were associated with a lower risk of mortality than when compared to those diets that replace carbohydrates with proteins and fats from animal sources.

However, the types of carbohydrates eaten in this study were not clarified.

Low-Carb Diet and Mortality Risks:

Several studies have found that a low-carb and high-protein diet significantly increases the risk of all-cause mortality.3

A study analyzed the relationship between low-carb diets and mortality in 462,934 participants. What were the results? People with the lowest carbohydrate intake (39% TDE) had the highest risk of cardiovascular disease, cancer, cerebrovascular disease, and overall mortality.4

Low-Carb Diets and Heart Health

People getting a low proportion of their daily calories from carbohydrates such as grains, fruits, and starchy vegetables are significantly more likely to develop atrial fibrillation (AFib), the most common heart rhythm disorder. Low-carbohydrate diets were associated with increased risk of incident atrial fibrillation, regardless of the type of protein or fat used to replace the carbohydrate.5

Not All Starches Are Created Equally

Rapidly digested starch breaks down quickly into simple sugars. The starch in white potatoes and refined baked goods digests very quickly, providing readily available glucose for the body’s needs.

Slowly digested starch breaks down into glucose in the small intestine, up to two hours. Other foods with high starch content, such as beans, barley, or long-grain brown rice, are digested even more slowly and cause a slower and lower rise in blood sugar.

Resistant starches are found in foods that often have a fibrous “shell,” making it harder for the digestive enzymes to reach them. Legumes are the best source of resistant starch, followed by grains. Cooling starchy foods after they are cooked increases resistant starches.

Health Benefits of Resistant Starch

Better Blood Chemistry

A meta-analysis revealed that consuming foods rich in resistant starches reduces the total and LDL cholesterol levels.6  Resistant starch seems to improve the ability of the cells to respond to insulin. Studies show that resistant starch consumption is linked to improved mineral absorption, especially calcium and magnesium.

Promotes Better Appetite Control

Resistant starch, when combined with protein, produces more satiety, or satisfaction, from a meal, improves fat burn, and is associated with less fat storage after that meal.7

Type 1 resistant starch (found in grains, seeds, and legumes) improves the ability of the cells to respond to insulin and improves fat burn.8  Resistant starch has been associated with an increase in certain gut bacterial populations that have been negatively correlated with type 2 diabetes.8

To get the most amount of resistant starch, let the grains cool before eating them. To get the highest level of resistant starch, cook the starchy food and refrigerate it overnight. It’s fine to reheat before you eat it.

Resistant starch reduces the pH level in the colon and substantially decreases inflammation, which may reduce one’s risk for colon cancer.9 10 

One Myth of Weight Management

True or False? A calorie from one food is the same as a calorie from another food. Not exactly true. Low-carb diets do seem to help weight loss, but the truth is that any diet that prevents the sudden surges in blood sugar helps weight loss. 11 It does not have to be a low-carb diet.

Benefits of Low-Glycemic Carbs

The glycemic index (GI) is a helpful system that allows you to see how the fruits, vegetables, and other carbohydrates you eat affect your blood sugar levels. It ranks food on a scale of 0 to 100. The diet that emphasizes low glycemic foods also results in weight loss. How? Foods with higher ratings of 70 to 100 produce a spike in your blood sugar levels and trigger your pancreas to release large amounts of insulin. This hormone facilitates the transport of glucose and fatty acids into your cells to be used as energy. While we need appropriate amounts of insulin, high levels of insulin circulating through your blood promote fat synthesis and make it difficult for your body to burn stored fat.

Low-GI foods release glucose more slowly and steadily. This consequently results in better blood glucose readings after a meal and prevents sudden surges of blood sugar and steep insulin levels. Studies show that the low-glycemic index diet has similar metabolic benefits to the very low-carb diet, with two important differences.

The low-glycemic diet does not produce the stress and inflammation seen on low-carb diets. In contrast, low-carb diets increase cortisol levels and C-reactive protein, a marker for inflammation.11

A low-GI diet offers another advantage. After weight loss, the rate at which people burn calories slows. 12 This makes it difficult for the needed weight loss to be maintained. A low-glycemic diet is effective at burning calories after weight loss is achieved.13

Eating foods at breakfast that have a low-glycemic index prevents a spike in blood sugar throughout the morning and after the next meal of the day. 14 Because low-GI plant foods are usually rich in fiber, they stabilize the blood sugar and promote satiety. Moreover, eating www.sciencedaily.com/releases/2009/03/090317201139.htm)) low GI foods increases the appetite-suppressing hormone GLP-1.((Society for Endocrinology. “Scientists Discover Why A Low GI Meal Makes You Feel Full.” ScienceDaily. ScienceDaily, 18 March 2009.

What Foods Score Low on the GI Index?

  • Most vegetables: cruciferous vegetables, salad veggies, greens, onions, eggplant, squash, sweet potatoes, carrots
  • Most whole grains: rye, barley, oats, spelt, millet, long-grain brown rice, whole grain pasta
  • Legumes: kidney beans, lentils, lima beans, split peas, black-eyed peas, green peas, almonds, peanuts, chickpeas
  • Seeds: chia, flax, sunflower, pumpkin, sesame
  • Fruits: cherries, prunes, dried apricots, grapefruit, apples, berries, pears

Pros and Cons of A High-Protein Diet

Eating a protein-rich breakfast curbs hunger and reduces unhealthy snacking on high-fat or high-sugar foods in the evening. A higher protein intake increases the hunger-fighting hormone known as peptide YY. 15 Eating more protein in the morning rather than packaged cereal also helps to prevent blood sugar spikes.

There are dangers in adopting a high-protein diet, especially if it is animal protein. Even though high-protein diets like Atkins do produce weight loss, rodent studies indicate that this type of diet is not the best for health. Mice fed a high-protein/low-carbohydrate diet had brains that were 5% lighter than those of the other mice, and regions of their hippocampus (important for mood and memory) were less developed. In other words, a high-protein diet shrinks the brain. 16

A diet rich in animal proteins during middle age makes you nearly twice as likely to die young and four times more likely to die of cancer. This mortality factor is comparable to smoking. 17

Replacing animal protein with legumes is a better, safer route. A systematic review and meta-analysis of all available clinical trials found that people felt 31 percent fuller after eating on average 160 grams (l serving) of dietary pulses compared with a control diet. 18  As previously mentioned, legumes score low on the glycemic index and are high in fiber.

Something Better: The Whole-Food, Plant-Based Diet

People shed more weight on an entirely plant-based diet, even if carbohydrates are included. Other benefits of eating a vegan diet include:

  • decreased levels of saturated and unsaturated fat
  • lower body mass indices
  • improved intake of nutrients

The ability to shed weight is faster for those who adopt a total vegetarian diet than for those consuming meat and dairy, or even those who eat a mostly vegetarian diet.

One study showed that at the end of six months, individuals on the vegan diet lost more weight than those individuals who ate a mostly plant based diet and those who were omnivores, by an average of 4.3%, or 16.5 pounds.19   A meta-analysis of 12 studies demonstrated that vegetarian diets are more effective than non-vegetarian diets for weight loss.20

In a 2020 meta-analysis of 38 studies lasting 6–12 months and including 6,499 participants, low-carbohydrate diets, defined here as <40% of energy from carbohydrate, led to a small weight loss, compared with low-fat diets, defined as <30% of energy from fat.31 Evidence suggests a low-fat, plant-based diet may improve satiety more than a low-carb diet.21

Conclusions:22

  • Sugar, products with high-fructose corn syrup, and refined carbohydrates sabotage our health and increase the risks of obesity, type 2 diabetes, metabolic syndrome, and mortality.
  • The nature of the carbohydrates rather than the amount is the key factor in reducing the risk of cardiovascular disease or in improving the cardiovascular risk markers.
  • Whole fruits and vegetables have fiber and a myriad of antioxidant and anti-inflammatory compounds.
  • Dietary fiber has a major and positive impact on the composition, diversity, and richness of the gut microbiome.
  • Resistant starch offers several important health benefits.
  • Low-carb diets and high-carb diets (that include sugar and refined grains) increase mortality risks.
  • Carbohydrates, when taken in an adequate amount and in the right balance in the diet, can sustain good mental health.
  • Nutrition guidelines recommend that carbohydrates make up 40% to 65% of total daily calories to fulfil body energy demands and to reduce the risk of some non-communicable diseases.

For more information on the health benefits of healthy, balanced plant-based diets, see the following links.

Does A Vegetarian Diet Help Diabetes?

How to Go Plant-Based for Beginners

Disclaimer: The information in this article is general and educational in nature. Wildwood Sanitarium, its entities, or authors do not intend this information as a substitute for proper diagnosis, treatment, or counseling from a qualified medical provider who knows the person’s medical history and laboratory work.

Copyright © by Wildwood Sanitarium, Inc. 2026. All rights reserved.

References:

 

  1. Tufts University. “Low-carb Diets Can Affect Dieters’ Cognition Skills.” ScienceDaily. ScienceDaily, 15 December 2008. www.sciencedaily.com/releases/2008/12/081211112014.htm[↩]
  2. Seidelmann, Sara B. et al. Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis. The Lancet Public Health, 2018; DOI: 10.1016/S2468-2667(18)30135-X[↩]
  3. Noto H. Low-Carbohydrate Diets and All-Cause Mortality: A Systematic Review and Meta-Analysis of Observational Studies. PLoS ONE. 2019.https://pmc.ncbi.nlm.nih.gov/articles/PMC6366685/[↩]
  4. Mazidi M., Lower Carbohydrate Diets and All-Cause and Cause-Specific Mortality: A Population-Based Cohort Study and Pooling of Prospective Studies. Eur. Heart J. 2019;40:2870–2879. https://academic.oup.com/eurheartj/article-abstract/40/34/2870/5475490[↩]
  5. American College of Cardiology. “Low-carb diet tied to common heart rhythm disorder: Study suggests using caution when restricting carbohydrates for weight loss.” ScienceDaily. ScienceDaily, 6 March 2019. https://www.sciencedaily.com/releases/2019/03/190306081652.htm[↩]
  6. Yuan HC, Meng Y, Bai H, Shen DQ, Wan BC, Chen LY. Meta-analysis indicates that resistant starch lowers total serum cholesterol and low-density (LDL ) cholesterol. Nutr Res. 2018 Jun;54:1-11. doi: 10.1016/j.nutres.2018.02.008.[↩]
  7. Gentile, C.L., et al. Resistant starch and protein intake enhance fat oxidation and feelings of fullness in lean and overweight/obese women. Nutr J 14, 113 (2015). https://doi.org/10.1186/s12937-015-0104-2[↩]
  8. Pugh JE, Cai M, Altieri N, Frost G. A comparison of the effects of resistant starch types on glycemic response in individuals with type 2 diabetes or prediabetes: A systematic review and meta-analysis. Front Nutr. 2023 Mar 27;10:1118229[↩][↩]
  9. Hylla S, et al., Effects of resistant starch on the colon in healthy volunteers: possible implications for cancer prevention. Am J Clin Nutr. 1998 Jan;67(1):136-42. doi: 10.1093/ajcn/67.1.136.[↩]
  10. Zimmerman, M. A., et al. (2012). Butyrate suppresses colonic inflammation through HDAC1-dependent Fas upregulation and Fas-mediated apoptosis of T cells. American journal of physiology. Gastrointestinal and liver physiology, 302(12), G1405–G1415.https://doi.org/10.1152/ajpgi.00543.2011 [↩]
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  14. Institute of Food Technologists (IFT). “Glycemic index foods at breakfast can control blood sugar throughout the day.” ScienceDaily. ScienceDaily, 30 March 2012. www.sciencedaily.com/releases/2012/03/120330110204.htmsciencedaily.com/releases/2012/03/120330110204.htm. [↩]
  15. Cell Press. “Eating Protein Boosts Hormone That Staves Off Hunger.” ScienceDaily. ScienceDaily, 6 September 2006. www.sciencedaily.com/releases/2006/09/060905225848.htmb[↩]
  16. BioMed Central. “Alzheimer’s Researchers Find High Protein Diet Shrinks Brain.” ScienceDaily. ScienceDaily, 21 October 2009. www.sciencedaily.com/releases/2009/10/091020192206.htm[↩]
  17. University of Southern California. “Meat and cheese may be as bad for you as smoking.” ScienceDaily. ScienceDaily, 4 March 2014. www.sciencedaily.com/releases/2014/03/140304125639.htm[↩]
  18. Siying S. L. Dietary pulses, satiety and food intake: A systematic review and meta-analysis of acute feeding trials. Obesity, 2014; 22 (8): 1773,  DOI: 1002/oby.20782)) [↩]
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