NEW YORK (Reuters Health) - If a large swath of the population cut down on calories and took up exercise, the resulting health benefits could be extensive, a new study suggests.
The findings are based on an analysis of the economic crisis in Cuba from 1989 to 2000. While the circumstances were dire, and Cuban citizens' health suffered in certain ways, researchers found that significant health benefits also emerged.
Specifically, people's overall calorie intake declined, while their physical activity levels climbed -- mainly as a result of walking or biking instead of paying for public transportation.
As a result, the prevalence of obesity fell by half -- from 14 percent of the adult population to 7 percent -- and deaths from diabetes, heart disease and stroke dropped substantially.
"This is the first, and probably the only, natural experiment, born of unfortunate circumstances, where large effects on diabetes, cardiovascular disease and all-cause mortality have been related to sustained population-wide weight loss as a result of increased physical activity and reduced caloric intake," lead study author Dr. Manuel Franco said in a statement.
Less-dramatic changes in diet and exercise -- ones that would not dampen the quality of people's diets -- could go far in reducing rates of heart disease and diabetes, according to Franco, of the Johns Hopkins University School of Public Health in Baltimore.
The findings, which appear in the American Journal of Epidemiology, are based on vital statistics and population surveys from the years 1980 through 2005. Franco's team found that after 1989, the first year of Cuba's prolonged economic downturn, calorie intake dropped substantially.
In 1988, the average person consumed 2,899 calories; that fell to 1,863 by 1993. Based on a number of population studies, the prevalence of obesity was cut in half over roughly a decade.
Even more importantly, the researchers found, deaths attributed to type 2 diabetes, heart disease and stroke dropped sharply between 1997 and 2002 -- by 51 percent, 35 percent and 20 percent, respectively.
There were negative health effects as well. Among elderly Cubans, the all-cause death rate actually inched upward and there was an epidemic of degenerative nerve damage as a result of widespread nutritional deficiency. During the economic crisis, rice and sugar cane were the staples of most Cubans' diets, Franco's team notes.
The adverse effects seen in this study could be avoided by cutting calories but maintaining a balanced, nutritious diet, according to the researchers.
"Future steps towards prevention of cardiovascular disease and diabetes should focus on long-term population-wide interventions by encouraging physical activity and the reduction of caloric intake," Franco said.
SOURCE: American Journal of Epidemiology, online September 19, 2007.