Probably not so much an issue in the summer time as it would be in the winter (assuming the rest of his diet is on par and he's working out consistently). We tend to put more fat on during the winter months as our bodies natural defense mechanism to deal with starvation (long, cold hungry days) begins to kicks in. Adding fruit (simple sugars) and other carbs to the mix as nature provides us with this extra later of insulation - is a recipe for an extra few pounds of fat around the waistline.
Or he can try it out for a few weeks and see what happens. Figured I'd save him the hassle though :>)