Conditions such as being overweight or obese, or having pre-diabetes or developing Type 2 diabetes, pose a particular threat, however, to national security, noted the researchers, epidemiologists in the DHA's Armed Forces Health Surveillance Division. Those conditions impact retention of service members and readiness, as they can render troops unfit for duty or make them non-deployable.

"The military services need to increase their emphasis on lifestyle modification to enhance health maintenance, wellness and general readiness optimization among service members," they wrote in the January Medical Surveillance Monthly Report, or MSMR, released Sunday.

According to the reports, service members' body mass indexes have increased overall since 1995, with the prevalence of obesity hovering at about 16% from 2018 to the beginning of 2020. But the pandemic exacerbated the problem, with more than 18% of U.S. troops diagnosed as obese in the last few years.

The largest relative increases occurred in those age 30 and younger. Military health care workers also saw the largest percent increases, as did the Marine Corps, in terms of relative change, even though Marines still maintain the lowest percentage of members with obesity than any of the other services.

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Others at greater risk for obesity, according to the studies, were non-Hispanic Blacks, Navy sailors, and those ages 40 to 44.

For pre-diabetes, health care workers also saw increased diagnoses, as did non-Hispanic Black service members. The Air Force saw the largest increases of the services.

Regarding Type 2 diabetes, the percentage of females diagnosed in 2021 was higher than the previous year, as were Navy sailors and Hispanic service members. Health care workers and those in the intelligence field had the highest rates for every year from 2018 to 2021.

The data was based on information drawn during periodic public health assessments of service members, many of which were conducted over the phone or, when conducted in person, depended on patient self reporting of height and weight. Because of cultural norms and professional obligations tied to physical fitness for service members leading some to potentially downplay weight gain, the data may actually reflect under-reporting, Defense Department health officials said.

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But, they said, the increases were somewhat expected, given the DoD’s move to remote work, closures of installation fitness centers and dining halls, implementation of travel restrictions, and force health protection guidance that limited physical training.

Stress and isolation related to the pandemic may also have played a role in the rise of eating disorders among service members, according to MSMR authors. Again, the numbers may have been under-reported, since they relied mainly on self-reported public health assessments. But pandemic life disrupted daily routines and had such an effect on social lives and mental health that the pandemic "likely contributed to the excessive eating disorder burden observed in 2021."

“While the impact of COVID-19 on eat­ing disorders should not be downplayed, it is more likely that psychosocial stressors of a pandemic, including social isolation, dis­ruption of daily routines, and food insecu­rity, compounded by military life, resulted in increased eating disorder burdens,” they wrote.

The Defense Department began its pandemic response in late January 2020 even before the World Health Organization officially declared the COVID-19 outbreak a pandemic, opening up facilities at California's March Air Reserve Base, Travis Air Force Base and Marine Corps Air Station Miramar to evacuees from Wuhan, China.

Throughout February and March 2020, installations overseas and at home began shuttering public spaces and reducing services. On March 25, 2020, Defense Secretary Mark Esper raised the Force Health Protection Condition Level for installations worldwide to Charlie, which restricted travel, closed schools and child care facilities, and implemented remote work.

Since February 2020, nearly 6,600 military service members, civilian employees, dependents and contractors have been hospitalized for COVID-19; 690 have died.

The Centers for Disease Control and Prevention and the U.S. Preventive Service Task Force have suggested that programs that focus on lifestyle changes are most likely to reverse chronic conditions such as obesity and Type 2 diabetes.

The researchers noted that the DHA and the Air Force have launched initiatives to focus on integrating "lifestyle medicine" into their health programs.

Research such as the "Blue Zones" project, which investigated the lifestyles of communities with the highest number of centenarians in their populations such as Okinawa, Japan, and Sardinia, have found that whole food, plant-based diets, daily activity, social interactions, adequate sleep and stress management, and avoidance of drugs or alcohol contribute to long lives.

"The mil­itary services need to increase their empha­sis on lifestyle modification to enhance health maintenance, wellness, and general readi­ness optimization among service members," the researchers wrote.