by - Because of their restrictive nature, low-carbohydrate diets, which provide less than 130 grams of carbohydrates per day, are often viewed as nutrient-deficient diets.
- However, a recent study analyzed the calorie and nutrient levels provided by well-planned low-carb and low-carbohydrate diet plans, suggesting that they can meet some of the nutritional needs of certain populations, especially middle-aged women.
- Although these diet plans can offer some benefits, they do not seem to meet everyone’s nutritional needs equally, as they may lack key nutrients and exceed recommendations for others.
- More research is needed, but health professionals recommend sticking to a moderate to high consumption of carbohydrates from nutrient-dense, plant-based foods for optimal health.
Low-carbohydrate diets are becoming more popular despite ongoing debates about the diet’s nutritional value and long-term health effects.
Now, adding to the discussion, a new study has been published in Limits in Nutrition evaluation of the calorie and nutrient content of three well-planned 7-day low-carb diet plans.
However, none of the low-carbohydrate meal plans could meet the caloric and nutritional needs of all genders and age groups studied.
The study received funding from Simply Good Foods USA, Inc, which owns Atkins and Quest Nutrition, brands that sell low-carbohydrate food products.
Additionally, employees of two of the three study authors are declared, and Simply Good Foods USA, Inc. is a shareholder.
Medical News Today contacted Simply Good Foods for comment regarding study funding and reported conflicts of interest.
In response, said Jonathan Clinthorne, PhD, study author and the Senior Director of Nutrition at Simply Good Foods MNT that: “The funder designed and modeled the dietary pattern using publicly available datasets and helped write the manuscript, along with a third-party expert. The study was peer-reviewed to ensure the scientific integrity of the work.”
Clinton also said:
“The goal of this study was to determine whether different levels of carbohydrate restriction could provide adequate nutrition, as this is a common issue with lower carbohydrate diets. The study uses food pattern modeling, a process that is easily repeatable for the research community, was peer-reviewed to ensure the scientific integrity of the work, and followed COI disclosure practices required by the journal. The study also transparently shows the nutrient adequacy and concerns when following these types of dietary patterns, which may help advance the scientific dialogue about low-carbohydrate diets.”
Low-carb diets typically involve eating less than 130 grams (g) of carbohydrates daily, which is less than 26% of a person’s daily calorie intake.
Very low-carbohydrate diets are even more restrictive, with only 20-50 g of carbohydrates per day, representing less than 10% of daily calories.
The researchers developed three separate diet plans, each providing 20, 40, or 100 g of net carbohydrates and varying amounts of other nutrients and calories each day.
“Net carbohydrates” refers to those digestible by humans, calculated by subtracting fiber and sugar alcohols from the total carbohydrates on a food label.
The food items were deliberately chosen to address them
The researchers assessed how well these plans met the recommended dietary allowances for men and women aged 31-50 and 51-70.
For women, all three low-carbohydrate 7-day meal plans generally met or exceeded daily calorie requirements, but only the 100-gram carbohydrate plan completely covered calorie needs for middle-aged women while exceeding them for older women.
On the other hand, for men across both age groups, all meal plans failed to achieve the recommended daily calorie intakes.
The meal plans, which replace carbohydrates with fats, had higher levels of fat and lower carbohydrates than generally recommended. Protein intake in these meal plans was higher than the recommended daily allowance for both sexes but was within the acceptable macronutrient range.
Men and women of all age groups on these plans will get more than many different vitamins, including A, C, D, E, K, thiamin, riboflavin, niacin, B6, folate, and B12, without exceeding maximum limits safe.
The plans also provided enough calcium for adults aged 31-50 but failed to meet the calcium needs of older adults.
Iron intake in these meal plans was adequate for older men and women, but middle-aged women – who need more iron – would not get enough iron, except on the 100 gram carbohydrate plan.
Saturated fat made up a significant portion of the total calories in each plan, with 21% in the 20 gram diet, 19% in the 40 gram diet, and 13% in the 100 gram diet. However, there was an improvement in these plans
Fiber intake, often a concern with low-carbohydrate diets, showed mixed results. Middle-aged males would not meet minimum fiber recommendations on these meal plans, and females would exceed them on 40 and 100 gram carbohydrate diets. Older females and males on the higher carbohydrate plans would also meet fiber requirements.
Adequate fiber intake is necessary to support a healthy intestinal system and to control cholesterol levels.
The 100 gram carbohydrate meal plan, the least restrictive, came closest to meeting nutritional goals, especially for middle-aged women. However, even as a well-planned diet, it is still short in some key nutrients and exceeds recommended limits in others.
MNT spoke with Thomas M. Holland, MD, MS, a physician and assistant professor at the RUSH Institute for Healthy Aging, RUSH University, College of Health Sciences, who was not involved in the study, to discuss the potential effects of the study. 100 gram carbohydrate meal plan.
The 7 day low carb meal plan included animal products at almost every meal, such as eggs, dairy products, meat, poultry, or fatty fish such as salmon, mackerel, sardines, or tuna.
Holland noted that the benefits of a similar meal plan “may come primarily from including high-quality protein sources such as dark, fatty fish,” which provide heart-healthy omega-3s that are linked to lower cognitive decline and reduced risks heart disease.
It is likely that the omega-6 to omega-3 ratio was better in the meal plans due to the regular inclusion of fatty fish.
However, the saturated fats from full-fat dairy and red meat, which exceeded the recommended limits, could increase LDL (bad) cholesterol and cardiovascular disease risks.
“Therefore,” said Holland, “while animal proteins provide benefits, the type of animal protein and the overall composition of the diet make a significant difference.”
Overall, when considering diet for optimal health, Holland said:
“While a low-carb, animal-heavy diet may have some benefits, especially when it includes healthy sources of protein such as fish, a plant-based diet that emphasizes high-quality whole foods is generally better for cardiovascular health, especially because of its higher fiber. and
phytochemical content.”
The study authors acknowledge that this analysis has limitations, such as not using data from actual dietary intake among free individuals to develop meal plans based on more commonly consumed foods, and not having consider dietary supplements.
They caution that, as with any meal planning for specific population groups, the meal plans and study results should not be personalized without taking into account age, gender, physical activity and pre-existing conditions.
Alyssa Simpson, RDN, CGN, CLT, a registered dietitian, certified gastrointestinal nutritionist, and owner of Nutrition Secrets in Phoenix, AZ, said she was not involved in the study. MNT while the study shows that low-carb diets may be nutritionally adequate for certain groups when carefully planned, “the challenge is whether people are eating high-quality, balanced diets in the real life”.
“Many low-carb diets rely on ultra-processed products, which may not offer the same health benefits as nutrient-dense foods,” she said.
She noted, for example, that ultra-processed foods such as “low-carb bars and shakes can be convenient for those following a low-carb diet, but products with high-quality ingredients and minor artificial sweeteners are essential to choose.”
Simpson said that “low-carb diets that are nutritionally complete and consist of high-quality, minimally processed foods are critical to achieving optimal health outcomes.”
Ultimately, regarding the low-carbohydrate dietary patterns of this study, she concluded:
“While low-carb diets can offer benefits, their long-term sustainability and adherence can be challenging. The study’s meal plans, while nutritionally adequate, may not fully address the practical difficulties individuals face when maintaining such diets over long periods of time.”
