For instance, an insurer won't take any interest in your diet, because that's hard to measure, but they will take a keen interest in your BMI and cardiovascular fitness.
The typical "wellness program" gives you a $X discount over the plan year in exchange for a 3rd-party call center company to collect your health information and nag you to not be so unhealthy over the phone at regular intervals. They have to tiptoe around ADA and anti-discrimination laws. The insurance discount is wholly insufficient to pay for any measure that would genuinely impact health. Given the choice between giving employees a direct $120 a year benefit for gym membership and splitting $50 discount to the employee and $70 expense to a professional call center nag, the group insurer invariably picks the latter.
You see, if you just give away the fitness gym membership, there's no leverage to make the employee actually go there and work out.
My current company invites people to get free blood pressure checks from staff of the local hospital system. I am not fooled by this. This is not motivated by concern for my health, but as a means to monitor the blood pressure of employees who already feel they must do so. The measurement is free, during business hours. Any intervention that might improve health, such as counseling or medication, has to come from the employee's own pocket, on their own time.
Although I am not very sure, what you really mean by saying "a lot of lifestyle changes needed to promote genuine health aren't really incorporated"...do you mean the employers don't promote them? Or the incentives you are relating to don't fall under the "wellness program" benefits in general to receive a credit/discount (from the standpoint of insurance companies)?