For generations, people have considered two distinctly different questions about eating habits: which diet is healthiest versus which diet results in the greatest weight loss. It has long been thought that the Mediterranean approach to eating is healthy, and new research has given additional credence to this fact.
The New England Journal of Medicine recently published the first large-scale study addressing the impact of how what we eat influences health outcomes. They focused on the Mediterranean Diet, and suggested for the first time that this way of eating is healthier than others. The Mediterranean Diet is characterized by: high intake of extra virgin olive oil, nuts, fruits, vegetables and cereals; moderate intake of fish and poultry; low amounts of dairy products, red meat, processed meats and sweets; and wine in moderation consumed with meals.
The study followed 7,400 people for an average of 4.8 years who lived in the Mediterranean (Spain) and randomly assigned them to one of three different eating plans. Two groups consumed variations of the Mediterranean Diet. These participants received free weekly allotments of either extra-virgin olive oil (about 4 tablespoons per day) or mixed nuts (1/4 cup daily of walnuts, almonds, and hazelnuts combined). The third group, a control group, consumed a diet designed to be low-fat.
The study was intended to look for three things: the incidence of stroke, heart attack, or death from cardiovascular causes. The researchers did not monitor changes in weight, cholesterol or blood sugar. The study found an impressive 30% lower risk of stroke in the Mediterranean Diet participants. There was no difference in the rate of heart attacks or in cardiovascular-caused deaths between the groups. However, the positive effect of stroke reduction was so pronounced that the study’s Safety Board stopped the study before its designated end date. They felt it would be unethical for the control group participants to continue on the low-fat diet.
Many researchers would have preferred that the study had been continued. Would a longer study have determined a difference in heart attacks or death rate (the other two indicators that were being studied)? Did the diet alter weight, cholesterol or blood sugar? Would a weight gain negate the study’s health improvements?
While the results point to a strong positive health benefit of the Mediterranean Diet, a major concern for Americans accustomed to large portions, is the ability to limit the intake of “healthy” but high caloric foods. For example, the Mediterranean Diet allows ¼ cup daily (approximately 200 calories per day) of mixed nuts. Nuts are a very high calorie food at approximately 800 calories per cup. Even though Mediterranean Diet participants consumed a small fistful of nuts, overall they ate about 100 more calories per day than the control group.
This study raises more questions than it answers, but it provides the first amount of reputable documented evidence that some foods contribute to better health. It is the first time that a large-scale study used scientific methods to examine the role of specific eating patterns on one’s health. The results bode well for future scientific studies to further investigate the role of how what we eat impacts our long-term health.