I would ask your doctor if you really want to know if it is healthy to do this with your wife. I think it is awesome that you want to do this with her.
52 year old (5'4")
Highest weight 234 (10 years ago)
Starting Weight 185.8 (4/10/12)
First Goal 160 (7/10/12) 161.2
Second Goal 155 (8/31/12)
Current Weight 166 and struggling (5/19/14)
Goal - 140# lose weight slowly, build muscle & lower body fat
"There is no diet that will do what eating healthy does. Skip the diet. Just eat healthy"