Study examines diet, exercise, obesity in prisons worldwide

Prison inmates in Tracy, Calif. A new study in the Lancet examines diet, exercise and obesity in prisoners.
(Luis Sinco / Los Angeles Times)

In a new study examining diet, physical activity and obesity in prison populations, researchers at the University of Oxford in England have found that in most cases, male prisoners are less likely to be obese than men in the general population. Female prisoners, on the other hand, were more likely to be obese than other women — at least, in the U.S. and Australia.

The findings, which were published Thursday in the journal Lancet (subscription required), reflect broader health disparities between advantaged and disadvantaged people, the researchers wrote.

They noted that in 2008, 36 million out of 57 million deaths worldwide resulted from non-communicable diseases such as heart disease, stroke, diabetes, cancer and respiratory disease. Vulnerable populations, including prisoners, are often hit hardest, they added.

“Most of the 9.8 million people imprisoned worldwide are from the poorest and most marginalised sections of society and are therefore likely to be at greater risk for non-communicable diseases,” the team wrote.


The Oxford researchers reviewed 31 studies that looked at more than 60,000 prisoners. The studies originated in Australia, Bangladesh, Cameroon, east Africa, Germany, the Ivory Coast, Japan, Nigeria, Pakistan, Romania, Russia, Taiwan, the United Kingdom, the U.S. and west Africa.

It wasn’t easy to get a uniform dataset, but trends emerged.

The team found, for example, a possible reason why the female prisoners were more likely than women in the general population to be obese. While male prisoners in high-income countries ate diets that provide “appropriate calorie intake,” female prisoners’ diets provided too many calories.

“The evidence suggests that female prisoners are simply supplied with a diet designed for males,” the authors wrote. “This finding is in accordance with current concerns that prisons are institutions designed by men for men with little concern for the needs of women who form a minority of the global prison population.”

Sodium intake was more than twice the recommended level in diets for both men and women in all nine studies where it was analyzed.

Results on physical activity (which were available only for Australia and the U.K.) were a mixed bag: prisoners in the U.K. were less likely to get the recommended amount of exercise than other people in the population; Australian prisoners exercised more than the general public.

The authors called on public health officials to intervene, writing, “Prisons have a responsibility to ensure that prisoners have access to healthy diets, with appropriate energy content and low sodium content as well as access to sufficient physical activity. However the data from this systematic review suggest that the opportunity is not being seized by prison authorities.”