What we need to think about is how this works practically. A billionaire isn't someone with a billion dollars in their bank account: it's someone with a 50% share in a business with a market cap of $2bn. How do we address that fairly?
Now I'd say that a business with a certain level of profitability owes something to its employees, such that very few businesses would reach that level of capitalisation.
The trick is to fit exercise into a routine. Work + sleep + family + study can add up to all of the available hours. Subsidised gym won't help with that.
Eating well: that also takes time. And planning. This is where we should be focusing our attention if we want to improve our country's health. Not weight loss jabs and not subsidising gyms.
Are you sure she isn't buying a new one each time?