It's our food supply. What we feed our sailors while deployed is toxic coupled with poor working and living conditions.
Increasingly I think it's a combination of the above and genetics.
The US Navy as an institution sucks when it comes to care for its people - especially sailors from low social/economic class.
I think Senior Navy leaders making it about will power and character are a joke themselves.
Advanced pharmaceuticals are the only hope in my humble opinion.
I would agree with you that the 28 day menu needs an overhaul. It's an elementary school lunch menu from the 1970s. I'm especially a fan (sarcasm) of the 1-2 punch on Saturdays - cheeseburgers and fries for lunch (with no salad / soup option because it's not popular) over pizza and wings for dinner. The CNO said he is trying to tackle this one, but competing with this is the combat logistics concern in a near-peer fight.
But there are measures the Navy can take besides that which are quick. Some of which may be very unpopular.
For starters, I think you get 80% the way there by setting the BCA standards at 26 BMI, and then doing a WtH ratio of < 0.51 for people who are over. You can lift heavy things to get built-fat after EAOS. Then you set the fitness standards at good low to pass in every event with FEP, good medium to pass without FEP. Review / standardize the bike to a timed distance event instead of a calorie count. There will be a lot of belly aching about how that's too hard to pass, but it's really not. Part of this needs to be a revamp of fitness at boot camp because it's currently producing some rather rotund sailors.
This creates a forcing function for triads to give a shit about making sure their sailors pass the PRT, because right now everyone knows you don't have to exercise to get a probationary and the BCA is a joke. PT standards are like any other standards - you do the training required to meet them.
You could go USMC style - command PT in-port / ashore at 0530 or 0600 every weekday, no exceptions. Only personnel who score excellent medium or better on all PRT events are exempt. Ships shall ensure this does not conflict with duty section turnover or other military duties. Create an accountability system for exercise underway. Boo hoo, you're in the military and that comes with mandatory exercise.
I think bringing in a nutritionist for a GMT as part of the 12-week notice would help. Eat your fruits and veggies.
Beyond that, we could look at things like banning energy drinks / soft drinks on ships, getting rid of vending machines on ships / installations entirely, or banning the sale of alcohol on-installation. You could get rid of desserts on ships with a stroke of a pen and no added logistics cost.
I think GLP-1 is a last resort if all of these measures get exhausted and prove to be untenable.