your mate lost 85kg, any kind of diet and lifestyle change would have had a dramatic effect on him if he has that much to loose.
nuts, beans, whole grains, dark leafed veg (spinach) provide plenty of iron, but you don't have to go full veggie.. i liked eating veggie cause you can can have a large meal that's relatively low in calories or fats. and it's dirt cheap. buy a good few recipe books to avoid repetition.
don't be to strict you'll start to resent it all, have a good day of cardio and have really awesome 'cheat' meals; expensive cuts of meat etc...