Scoring dietary habits
The current study, which comes out of a larger study called the European Prospective Investigation into Cancer and Nutrition--Physical Activity, Nutrition, Alcohol Consumption, Cessation of Smoking, Eating Out of Home, and Obesity project (EPIC--PANACEA), included data from more than 373,000 people in ten European countries. The people in the study filled out detailed dietary surveys and their eating habits were scored for how closely they matched a Mediterranean dietary pattern (MDP).
The MDP score was based on nine characteristics of a Mediterranean diet:
- eating high amounts of olive oil, vegetables, fruits and nuts, legumes, fish and seafood, and cereals;
- drinking alcohol moderately; and
- eating low amounts of meat and dairy products.
A score of 0-2 was assigned to each of the nine characteristics, so that the total MDP score ranged from 0-18, with a high score reflecting close adherence to the MDP. Once calculated, participants' scores were compared with their weight changes over five years.
Small but significant
The results showed that eating a Mediterranean-style diet was associated with slightly less weight gain and a lower risk of becoming overweight or obese:
- For every 2-point increase in MDP score, 0.05 kg (0.11 pounds) less weight was gained during the five-year study.
- People with a high score (11-18) gained 0.16 kg (0.35 pounds) less weight and were 10% less likely to become overweight or obese during the study than people with a low score (0-6).
"This observational prospective study shows that eating a Mediterranean-like diet may help to prevent weight gain and the development of overweight and obesity," the study's authors said of their findings.
The researchers then looked at each component of the MDP separately to determine whether certain characteristics were especially important. "The low meat content of the Mediterranean diet seemed to account for most of its positive effect on weight gain," they reported.
Get the meat out
This study suggests that we can add obesity prevention to the growing list of health benefits linked to the Mediterranean diet. One previous analysis involving 1.5 million healthy adults found that following a Mediterranean diet reduced the risks of overall and cardiovascular mortality, cancer and cancer mortality, and Parkinson's and Alzheimer's diseases.
If you're making the switch to a Mediterranean diet, remember these important aspects:
- Cut down on meat. Have small portions infrequently, and choose plant-based alternatives like protein-dense beans and lentils whenever possible. Cold-water fish like wild salmon, tuna, and herring are another good meat-replacement once or twice a week.
- Beef up on fruits and vegetables. All healthy diets emphasize fruits and vegetables, and this one is no exception. Aim for seven to ten servings per day.
- Unrefined is the rule. Choose whole grains like wheat berries, bulgur wheat, brown rice, and oats instead of refined grain products such as breads, pasta, and crackers made from white flour.
- Pick healthy fats. Olive oil is a Mediterranean staple. It can be used instead of butter on cooked or raw vegetables and in many recipes. And don't feel guilty about having nuts and seeds as snacks or in salads or other dishes--they are firmly established as heart-healthy.
- Celebrate with a glass of wine. Two glasses for a man and one glass for a woman every day is just about right, but check with your doctor if you have a health condition that might make drinking any alcohol a poor choice.
(Am J Clin Nutr 2010;92:912-21)