London, June 23: Researchers at the Harvard School of Public Health (HSPH) have found that modest changes in specific foods and beverages, physical activity, TV-watching, and sleep duration were strongly linked with long-term weight gain.

Changes in diet, in particular, had the strongest associations with differences in weight gain.

The researchers evaluated changes in multiple dietary and other lifestyle factors and weight gain every four years over 12 to 20 years of follow-up in three separate large cohorts, the Nurses' Health Study (NHS), the Nurses' Health Study II (NHS II), and the Health Professionals Follow-up Study (HPFS).

The final analyses included 50,422 women in the NHS, 47,898 women in NHS II, and 22,557 men in HPFS, all of whom were free of obesity or chronic diseases at the beginning of the study.

Study participants gained an average of 3.35 lb during each four-year period, which corresponded to a weight gain of 16.8 lb over the 20-year period.

Foods associated with the greatest weight gain over the 20-year study period included potato chips, other potatoes, sugar-sweetened beverages, unprocessed meats and processed meats.

The results also showed that changes in physical activity and TV-viewing influenced changes in weight.

Also, those who slept 6-8 hours a night gained less weight than those who slept less than 6 or more than 8 hours.

Overall, the weight-changes associated with lifestyle change were fairly small. However, together they added up, especially for diet.

"Small dietary and other lifestyle changes can together make a big difference - for bad or good," said lead author Dariush Mozaffarian, associate professor in the Department of Epidemiology at HSPH.

The study appeared in the June 23, 2011, issue of the New England Journal of Medicine. (ANI)