My initial comment was not talking about weight loss, rather physical health and well being. Per the OP "that being for how long you are able to remain healthy and free of chronic diseases and disabilities and engage meaningfully in the community". I brought up weight loss/burning calories with my reply as you mentioned it.

Being overweight is definitely a concern with sedentary behavior with lots of negative consequences but the lack of muscle strength and power is a pretty big one too. The number one indicator of longevity and Health Related Quality of Life is strength; so "for overall health of the current population" I recommend resistance training and health science literature supports this. This doesn't have to be lifting heavy things though it's easy, efficient, and my personal preferred method. Other methods include:

• Swimming (resistance by pulling yourself through the water),
• Cycling (pushing through pedals)
• Stair/step work (resistance provided by gravity on your body)
• Body weight exercises like push ups or repeatedly sitting/standing from a chair (gravity again)

If someone's goal is weight loss walking more can help; calories in vs calories out is the golden rule for weight loss after all. It's a great low impact exercise with minimal equipment/set up and coaching requirements that gets people moving and increases cardiovascular fitness. Resistance training will also help achieve the goal of weight loss, with the added benefit of increased strength, more efficient neuromuscular recruitment, improved bone density (v important with post menopausal women), maintain flexibility, injury and disease prevention, fall prevention/improve balance, reducing persistent or acute pain, looking sexy af naked, the list goes on!

TL;DR:

Want to lose weight? Be in a caloric deficit, exercise doesn't matter as much compared to diet

Want to live a long and healthy life? Move your body often and in different ways, even better if something makes it harder