This article is a collaboration between MedPage Today and:

ORLANDO -- Cooking meals at home was associated with a slightly lower risk of developing type 2 diabetes, said researchers at the annual conference of the American Heart Association here.

Those who ate 11-14 lunches or dinners prepared at home per week -- or about two meals per day -- faced a lower risk of diabetes compared with those who ate only six or fewer homemade meals a week (hazard ratio 0.87). The research was presented by Geng Zong, PhD, at the Harvard T.H. Chan School of Public Health, during a news conference at the meeting.

The authors also found that in 8 years of follow-up, those who ate more meals prepared at home had lower weight gain and risk of obesity (HR 0.87 for obesity), which could have accounted for the lower diabetes risk, said Zong.

"We tried to analyze the differences in the diets of these people, and we also found that those with more meals prepared at home have a slightly lower sugar sweetened beverage intake," said Zong. "This could be another bridge that links homemade meals and diabetes risk."

There was not enough data to include breakfast habits. Data were taken from about 58,000 women in the Nurses' Health Study and 41,000 men in the Health Professional Follow-up Study. Follow-up time was about 26 years, from 1986 to 2012. Both of those studies were observational and included men and women ages 40 to 75. Every 2 years, the participants reported lifestyle and health status and at baseline, none of the participants had diabetes, cardiovascular disease, or cancer.

"The trend for eating commercially prepared meals in restaurants or as take-out in the United States has increased significantly over the last 50 years," said Zong in a press release. "At the same time, type 2 diabetes rates have also increased."

Previous research has indicated that eating out generally means poorer diets. A 2012 study found that children and teens ate more food that had a worse nutritional content when they ate out -- regardless of the type of restaurant.

Eating five-seven lunches per week prepared at home was associated with an 8% decreased risk of developing diabetes compared with those who at zero-two homemade lunches a week. The decrease was larger for dinner: those who ate dinner prepared at home nearly every day had a 14% decreased risk.

Women who ate at home most often had a -0.42 kg weight change, and men had a -1.25 kg weight change compared with those who rarely cooked.

Limitations of the data included its reliance on observational studies and lack of information about what type of meals were prepared at home. In addition, all of the participants were health professionals so the results may not be generalizable.

"Action is needed to improve the quality of diet from commercial sources, because the need for convenient food remains," concluded the authors.