What issue undermines people's health the most and what steps should be taken to change it?

I believe the issue is unnecessary consumption of sugar.

The amount of sugar that average people consume everyday could contribute to   around 300-600 of their caloric intake each day, which would increase the risk of developing diabetes. The steps that should be taken to deal with this issue is to increase people's awareness about this issue through campaigns or advertising and providing substitution for this product.

Fast living lifestyle, Unhealthy eating habits (junk food), Late nigh sleeping habits, Desk jobs are some of the issue which causing health issues in people.

To change these bad habits people need to adopt good and healthy eating habits as food is the first and main component which provided energy to the body for all day activities.

People need to be more punctual about their sleeping time. 7-8 hour sleep is necessary for a fresh and energetic day. Along with the jobs people needs to add some physical workout and exercise to keep them fit and healthy.

u idek                                                                                                                                               /