When we had to fatten ours after her egg laying, we found that if we gave her too much mango or too many berries (her favorites) she would pick them off and not eat her greens or squash. We started breaking or cutting small amounts up (like one berry) and placing it around the top of her food. It drew her attention and she’d immediately come down to eat and eventually lick the plate almost clean.

Some others will probably be able to give you some other recommendations, but we haven’t had to add packaged diet to fatten yet (though we were considering it at a certain point for our new baby and the older female I mentioned above, but both decided to fatten themselves up!).

Once an iguana suffers from malnutrition and is thin it takes a long time to regain normal weight. These are before and after photos of an emaciated iguana that we took in 3 years ago. You can see that it has no flesh at all in it’s tail in the first photo. It took about 9 months to get the iguana up to normal weight.