Pro-inflammatory diets lead to weight gain

Last year we wrote an article summarizing current research on inflammation and diet. Chronic inflammation, which we know contributes to your risk of heart disease and cancers, is more common in those who consume a more Westernized diet, which includes more trans and saturated fats, omega-6 fats (as opposed to omega-3s), sugar, and alcohol. A Mediterranean Diet, on the other hand, is a more anti-inflammatory diet, and we've seen that a Mediterranean Diet reduces your risk of those inflammation-related illnesses.

James Hébert, a Health Sciences Distinguished Professor at the University of South Carolina, has created a "dietary inflammatory index" to measure the relative pro-inflammatory level of a person's diet. His research analyzes nearly 2,000 research articles evaluating 45 food parameters with respect to whether those parameters increase or decrease markers of inflammation in the bloodstream. If the item increases inflammation, it receives a +1 score, if it decreases inflammation, it receives a -1 score, and it receives a zero (0) if the item causes no change in the biomarkers of inflammation. An overall dietary inflammation score is thus called a DII (Dietary Inflammatory Index), and a lower score would be considered better than a higher score.

For this research, Dr. Hébert and a team at the University of Navarra in Pamplona, Spain used data gathered from an ongoing study known as the Seguimiento Universidad de Navarra [University of Navarra follow-up], which began in 1999 (Obesity 2017(25):997-1005). The study includes over 21,000 men and women who respond to a semiquantitative food frequency questionnaire administered every two years. The participants also report on their health, height and weight, and other demographic information like family health history.

Dr. Hébert and his team chose to include for this analysis only those men and women who started the study at a clinically normal weight, were under 65 years of age, were not pregnant or did not become so over the 12 years of follow-up, and whose reported caloric intake were within reasonable parameters - about 7,000 men and women. The authors used those participants' food frequency questionnaires to assign each participant a DII score as well as a Mediterranean Diet score.

The researchers' focus was on the association between the amount of weight gained over the course of follow-up and the individual's dietary scores, whether DII or Mediterranean Diet.

Those with the highest (poorest) DII scores gained more weight, and were more likely to become overweight or obese, than those with the best (lowest) DII scores. This held true even after the researchers took into account relevant variables like caloric intake, smoking status, family history, and physical activity.

The authors conclude that a "a more proinflammatory diet... was directly associated with the risk of developing overweight or obesity."

What this means for you

Dr. Hébert states in the disclosure portion of this article that a company in which he has controlling interest plans "to license the right to his invention of the dietary inflammatory index... in order to develop computer and smartphone applications for patient counseling and dietary intervention in clinical settings." We must caution you that the question of weight gain is larger than whether you are consuming pro- or anti-inflammatory foods - we can just see another fad diet arising out of this research. While this team of researchers took into account caloric intake when performing their analyses, we also know that higher quality calories, which are very often less-inflammatory calories, are often of lower caloric density and of higher nutrient density than those foods that are pro-inflammatory. On a day-to-day level it's far simpler (and just as effective) for you to focus on your Mediterranean Diet score (without worrying about weight loss): here's what makes up your score, with tips to improve it.

First posted: November 29, 2017