Is it effective? Yes, it is, but the better question is, is it safe? The answer is that no diet is safe unless it is sanctioned and monitored by your physician.
Plan to eat no more than 1500 calories a day. The suggested foods include half a grapefruit, toast, tuna, coffee, eggs, apples, cheese, and vanilla ice cream.
You can drink black coffee, tea and water if you want. But you cannot have milk, soda, or alcohol. You can make substitutions for any food allergies or sensitivities or if you are vegan.
As such, strenuous exercise like weightlifting is discouraged. Instead, low-impact activities like yoga, walking, and tai chi are encouraged.
Once you meet with your doctor and get their approval, the diet is an easy, simple way to change your eating habits.