Can the paleo diet make metabolic syndrome ancient history?

Approximately 25% of the adult U.S. population^[1] has metabolic syndrome, a condition that greatly increases the risk of diabetes and cardiovascular disease^[2] (CVD). Though the exact definitions may vary, metabolic syndrome is characterized by insulin resistance and is classified as a cluster of at least three of the following risk factors:

• Abdominal obesity (waist circumference greater than or equal to 102 cm in men or 88 cm in women)

• Fasting blood glucose of 100mg/dL or higher

• Serum HDL cholesterol below 40mg/dL for men or 50mg/dL for women

• Serum triglycerides of 150mg/dL or higher

• Blood pressure elevated above 130mmHg systolic or 85mmHg diastolic

• Use of medication to achieve healthy ranges of blood glucose, cholesterol, triglycerides, or blood pressure.

When we consider the daily activity levels of people prior to the 20th century, it becomes clear that we are in the midst of a genetic mismatch between our genes and the environment. The modern lifestyle includes 24/7 availability of salty, sugar-laden, high-fat foods along with unnatural exposure to artificial light and the ability to go days, weeks, months, or even years without walking for longer than five minutes in a row. Acknowledgment of this genetic mismatch coupled with declining health statistics has led researchers to consider the foods that were being eaten prior to not only the industrial revolution, but also before the agricultural revolution (the past 10,000 years, when the cultivation of grains, legumes, and dairy began).

An oft-cited criticism of the “paleo” diet is that there was not one specific ancestral diet. However, a number of research^[3] papers^[4] have used similar diets focusing on lean meats and fish, fruit, vegetables, eggs, nuts, and seeds, while removing grains, legumes, added sugars, and dairy products. Irrespective of what people actually ate during those times, this incarnation has established itself in research and practical use as “the paleo diet.”

Previous studies have used healthy^[5] subjects, as well as people with diabetes^[6], CVD^[7], and obesity^[8]. However, up until now, no studies have focused on people with metabolic syndrome. Since many of the previous studies that showed beneficial effects of a paleo diet also included weight loss, it is not clear whether the favorable effects were due to the weight loss itself or to the composition of the diet. The purpose of this pilot study was to compare the metabolic effects of a paleo diet to a generally healthy reference diet, in the absence of weight loss, in people with metabolic syndrome.

Metabolic syndrome is defined as a cluster of metabolic problems that increase the risk of cardiovascular disease and death. Previous research on “the paleo diet” has not focused on subjects with metabolic syndrome, and had weight loss as a possible confounding factor.