Yeah, and also, he may be experiencing prolonged insulin production due to what kind of foods he's eating as well. The attendant low blood sugar will increase the appetite. There are a number of possible factors, and the increase in proteins/fats without increasing the calories is a fast and dirty method to maybe compensate for the cravings and control them.

lbb makes an excellent point about the types of foods you are eating though techno.....

Keep a journal of everything that you eat and drink and see if there is a trend of foods that may stimulate increased insulin production.

edit: Also, with the higher protein intake, remember to up the hydration. Your kidneys will thank you for it.

also, keep some glucose tabs in case you experience a severe low blood sugar event, and think about a diabetes screening as well, since these "cravings" can be an indicator of a prediabetes condition.