Sea mammals need that extra layer of fat.

Walruses, whales, manatees... sailors:

For the Navy, the overall number of obese personnel was a shocking 22 percent. The other branches reported the following frequency of obesity:

• Air Force: 18 percent
• Army: 17 percent
• Marine Corps: 8.3 percent

ADDED: Remember that the military excludes would-be recruits who are obese. From a report from 750 retired generals and admirals issued last fall:

According to... “Unhealthy and Unprepared,” an estimated 71% of all young people in the U.S. between the ages of 17 and 24 do not qualify for military service. Obesity disqualifies about 31% of youth, the report specified....

Retired Lt. Gen. Samuel Ebbesen said Mission: Readiness has been warning the country about the impact of obesity on national security for nearly a decade. He said acting now to address the issue was critical to the nation’s future defense....

So those numbers — 22% of the Navy, 18% of the Air Force, 17% of the Army, 8.3% of the Marines — those are all from those who did get in, who were not among the 71% who are disqualified. They are from the 29% least fat young people, and they are subjected to military training and discipline. There really is a problem, and yet the first comment on this post is an exemplar of denial:

Probably defined as obese by having a BMI > 30. Could be fat, could be muscle, or some combination of both, but my guess is a lot of these sailors spend a lot of down time in the weight room.

Another commenter says:

These new servicemen might be tubby, but I am a BMI skeptic. They say 30 is obese on the charts. A 6'0" man who weighs 215 has a BMI of 30. That could be a bit flabbly but also could be muscular/strong. It would rarely be obese if the man is at all active (can walk 5 miles, work outside for 3 + hours, do moderate sports activities, etc.).

On the other end, the charts say if that same man lost almost 100 pounds -- 135 -- he would be "normal." The very edge of normal, but normal nonetheless. Sorry, 135 is not normal weight for a 6' man. That's stick-like. What Arnold might call a girly man whose pants have to be cinched by a rope.

BMI is fake news. It's an uneasy comparison to think about, but obesity is a bit like pornography -- I know it when I see it.

BMI skepticism is, apparently, the new "I'm not fat, I'm big boned."