A recent study published in Frontiers in Nutrition has dispelled longstanding doubts about the nutritional adequacy of low-carb diets, confirming that these meal plans not only meet but can surpass essential nutritional needs. This research challenges previous criticisms that low-carb diets might lack necessary nutrients and instead highlights their potential to enhance overall diet quality and health outcomes.
Over the past decade, low-carbohydrate diets have seen a surge in popularity, with many adopting these diets to improve health and manage or reverse type 2 diabetes. Despite their rising acceptance, critics have raised concerns about their nutritional adequacy, suggesting that reducing carbohydrate intake could lead to deficiencies in essential nutrients due to a potential increase in protein and fat consumption.
The new study assesses three distinct low-carb meal plans over a period of seven days: two ketogenic diets—one with approximately 20 grams of net carbs per day and another with about 40 grams of net carbs per day—and a more liberal plan with around 100 grams of net carbs daily. (Net carbs are calculated by subtracting fiber from total carbohydrates.) All three meal plans adhered to the definition of a low-carb diet, which is characterized by a daily intake of less than 130 grams of carbohydrates.
Nutritional Benefits of Low-Carb Diets
The study’s findings reveal that all three low-carb meal plans exceeded the nutritional requirements for vitamins A, C, D, E, K, thiamin, riboflavin, niacin, folate, and vitamins B6 and B12 for adults aged 31-70.
Dr. Beth Bradley, a co-author from the Department of Nutrition and Food Sciences at the University of Vermont, emphasizes, “Many Americans struggle to meet their nutritional needs from conventional diets. Our research indicates that, alongside their well-documented benefits for weight management, low-carb diets can significantly improve diet quality and address nutrient deficiencies.”
The study notes that while a few nutrients, such as iron for younger women and calcium for older adults, were slightly below recommended levels in some meal plans, the majority of essential nutrients were adequately provided. The more liberal low-carb plans, with 40 and 100 grams of net carbohydrates, also met fiber needs for women aged 31-70. This is particularly relevant given the popularity of low-carb diets among middle-aged women.
Dr. Bradley further explains, “The notion that low-carb diets must be low in fiber is not supported by our data. Fiber-rich foods, such as non-starchy vegetables, nuts, seeds, and, in moderation, higher-carb fruits, starchy vegetables, and whole grains, can be included in low-carb diets to maintain fiber intake while keeping net carbs in check.”
Macronutrient Balance and Nutrient Ratios
The study also examined the macronutrient distribution of the meal plans. All three low-carb diets provided protein levels exceeding the Recommended Dietary Allowance (RDA) but within the Acceptable Macronutrient Distribution Range of 10-35% of daily calories, thus avoiding excessive intake.
Although the diets contained slightly higher levels of saturated fat and sodium compared to average American diets, they also demonstrated improved omega-6 to omega-3 and sodium-to-potassium ratios, which are associated with better cardiovascular health and reduced risk of type 2 diabetes.
Dr. Bradley adds, “Nutritional quality is not just about the quantity of nutrients but also the sources and their broader dietary context. Improved ratios of omega-6 to omega-3 and sodium to potassium have been linked to better health outcomes, including lower risks of cardiovascular disease and hypertension.”
The study supports the growing body of evidence that a low-carb lifestyle can offer robust nutritional benefits and help manage or reverse diet-related diseases. While some individuals, such as younger women and older adults, may need dietary supplements to fully meet their nutritional requirements, low-carb diets provide a strong foundation for maintaining overall health.
This research was supported by Simply Good Foods USA, Inc., which played a role in designing and analyzing the dietary patterns and manuscript writing. The study’s authors from Simply Good Foods USA, Inc., which owns Atkins and Quest Nutrition, have disclosed their affiliations and potential conflicts of interest.
