Collards, Carrots and Lentils

A new study published yesterday in the Archives of Internal Medicine suggests that both weight loss and risk factors for heart disease can be improved following a vegan version of the low-carb, high-protein Atkins diet.

The “Eco-Atkins” diet focuses primarily on soy, nuts and wheat proteins (gluten) to increase the amount of vegetarian protein in the diet. Carbohydrates were restricted to 130 g/day, which is on the higher end of most low-carb diets. All starchy foods such as bread, baked goods, potatoes and rice were eliminated. Carbohydrates were provided in the form of whole, intact grains (barley and oats) and low-starch vegetables.

In a small (47 participants), short-term randomized controlled trial, this diet lowered bad LDL cholesterol by 20%, without negatively impacting good HDL cholesterol (statin drugs improve cholesterol levels by 30%). The diet also substantially lowered blood pressure and other markers of cardiovascular disease, such as triglycerides and apolipoprotein B.

The original meat-based Atkins diet has been shown to be effective for temporary weight loss (after 1 year the effects of the Atkins diet are diminished), but cardiovascular risk factors such as LDL cholesterol and blood pressure are not substantially improved under the traditional Atkins regimen.

Interestingly, a traditional Atkins-style diet based on animal protein was not used as a control in this study, so a true comparison of the diets cannot be made using the present data. Instead the researchers chose a control diet representative of a typical high-carb, low-fat vegetarian diet that included eggs and dairy products. Both diets tested in this study represented a 60% decrease in total calories.

Because of the study design, we cannot conclude that this diet is more effective than the Atkins diet for health, though you would predict it would be if future studies made this comparison. On the other hand, it does seem that a plant-based high-protein diet is more effective at improving health than a high-carbohydrate lacto-ovo vegetarian diet, at least in the short-term in a highly controlled environment.

This study took place over the course of 4 weeks, and all the food was provided for the particpants by the researchers. Thus, compliance in the program was very high. It is not clear if the participants would have had the same level of success if they were instructed to provide their own food to comply with the dietary programs.

Despite this, satiety levels were notably improved in the high-protein group and it would be expected that the increase in satiety would encourage greater compliance in a free living situation.

A small four week study, however, tells us very little about the effectiveness of this diet. While it is possible to improve risk factors such as cholesterol and blood pressure in such a short period of time, disease outcome is the true measure of a successful diet. Also, this study did not test the feasibility of the Eco-Atkins diet in the long-term, and it is likely many dieters would object to a strictly vegan regimen.

Interesting points raised by this preliminary study include:

• Plant-based, high-protein diets may be more effective at improving cholesterol and other cardiovascular measures than traditional lacto-ovo vegetarian diets.
• Short-term weight loss is primarily determined by the number of calories consumed, not macronutrient content.
• Low-carb diets that include intact whole grains and plant-based protein can be effective at improving both weight and cardiovascular risk factors in the short-term.
• Plant-based high-protein diets can increase satiety compared to high-carb vegetarian diets.

However, many questions must be addressed before this diet can be recommended to individuals trying to improve cardiovascular measures and lose weight.

New questions:

• Can the Eco-Atkins diet be maintained in the long-term by normal individuals?
• Does the Eco-Atkins diet continue to improve cardiovascular risk factors including weight loss after 4 weeks?
• What would result from this study if beans and lentils were used instead of soy and gluten?
• Does the Eco-Atkins diet improve disease outcome?
• Does the Eco-Atkins diet extend life?
• Does the Eco-Atkins diet affect quality of life?
• Can these effects be attained through other diets that include some animal protein, more whole grains or more fat?
• Is the effectiveness of the Eco-Atkins diet affected by an individual’s level of insulin resistance?
• Can adding fish further improve the results of the Eco-Atkins diet?
• Can a further reduction in carbohydrates improve the results?
• Will you get these same results if the study is NOT funded by the soy industry?

In summary, the results of this study are interesting and encouraging, especially for those of us who think both carbohydrates and meat should be limited in a healthy diet. I very much look forward to future studies exploring this idea.

What concerns me most is the lack of marine omega-3 fatty acids (fish) in the Eco-Atkins diet, which could potentially improve cardiovascular measures even further. Fish is also important for cognitive health and may lower cancer risk.

I am also worried that a strictly vegan diet would not be feasible in the long-term for many Americans. Moreover, it is not necessarily the healthiest option available. Vitamin B12 deficiency is a particular concern, but could be addressed with supplements. Generally, however, I do not recommend relying on supplements for optimal nutrition.

Finally, this study was funded by a company that makes soy and gluten products. Personally I would have prefered to see these protein sources used in combination with other things such as beans and lentils. Many people question how much soy can be safely consumed and gluten intolerance is more common than ever, so wouldn’t it be interesting to know if there were safer alternatives? It really annoys me to see science being influenced by industry funding.

What do you think of the Eco-Atkins diet?