Can health insurance company mandate that you attend weight loss programs and if you don't raise your premiums

Received a letter from insurance company stateing that because my husband has a body mass index of 30 he must visit his physician every 6 months & must complete multiple questionairres. If he chooses not to do this his benefit level will decrease. The insurance is paid for by his employer. He currently gets a physical yearly & has normal blood pressure & cholesterol & other labs. - Is this your question? Add additional information