I assume you’re referring to the recent statics about the number of people who are unable to serve because their weight would not allow them to pass the military fitness test. The military is also addressing this issue with ongoing fitness tests, weight management programs, exercise and nutrition programs, hiring additional personal to work with servicemembers, etc.
Is this an issue of “national security”? I’m not sure. Is it a concern? Yes.
National security implies that our servicemembers would not be up to the task of defending our freedoms or those of others, should the situation arise. I think our servicemembers have repeatedly demonstrated that they will do whatever is needed, including their lives, to defend those freedoms and those who live under them. However, as others have noted, obesity is not a healthy state to live in. It shortens a persons lifespan, puts them at risk of developing high blood pressure, diabetes, heart disease, stroke, various cancers, etc. Like other industries, the medical costs of keeping an obese person healthy are more than a person of “normal” weight. The risks of poor diet and not enough exercise takes a toll on a person’s mental and physical capacities as much in the military as they do in civilian life. Those same concerns of decreased health, increased medical costs, decreased work efficacy and shrinking budgets that the civilian population and industries struggle with as the obesity rate continues to climb, is also the same concerns within the military, and remember it is taxes and federal budgets that pay for our military, so their concerns are all of our concerns.
So to answer your question simply….no it is not a concern of national security as our servicemembers will answer the call to defend our freedoms from any threat as they have demonstrated in all conflicts to date.
Is it a public or military concern? Yes, as obesity should be in any industry and in our society as a whole.