from the link in your question:
How premiums are set
Under the health care law, insurance companies can account for only 5
things when setting premiums.
Age: Premiums can be up to 3 times higher for older people than for younger ones.
Location: Where you live has a big effect on your premiums. Differences in competition, state and local rules, and cost of living
account for this.
Tobacco use: Insurers can charge tobacco users up to 50% more than those who don’t use tobacco.
Individual vs. family enrollment: Insurers can charge more for a plan that also covers a spouse and/or dependents.
Plan category: There are five plan categories – Bronze, Silver, Gold, Platinum, and Catastrophic. The categories are based on how you
and the plan share costs. Bronze plans usually have lower monthly
premiums and higher out-of-pocket costs when you get care. Platinum
plans usually have the highest premiums and lowest out-of-pocket
Factors that can’t affect premiums
Insurance companies can’t charge women and men different prices for the same plan.
They also can’t take your current health or medical history into account. All health plans must cover treatment for pre-existing
conditions from the day coverage starts.
In the united states especially after the passage of the ACA there no requirement for a physical exam.
The policy rates are set based on the experience of the previous year, and if they expect that the population of customers will be changing. they know their age, zip code and that's about it.
Most policies are group policies. People get them from their employer who has enough employees and their families to be a group, or the employer join a group through a company such as ADP. Other people get their policy via one of the exchanges setup under the ACA, or though a government program such as Medicaid or Medicare.
The people running the group policy try to entice people to be healthy by paying them an incentive to do healthy things. They may pay for a program to quit smoking. Or give them a discount if they use a fitness tracker and meet certain goals. If the group is younger and healthy than the model then they can make more profits. Though profits are limited by the ACA.
When getting a group health insurance policy there has been zero requirement for a physical, or any way to prove that I am healthy. They ask for my DOB, but not my height, weight, or family history. They have no access to Apple watch data, or any other tracker, unless I give it to them.
Obesity of the person is not considered when setting the rate. It is part of the equation for life insurance but not for health insurance.
It can get even more complex for the large corporations because they frequently self-insure. They pay a company for the access to the doctors and hospitals and to process the claims. But the expenses are paid by the employer and the employee.