Hi!
What guinea pigs should eat most of is hay, hay and more hay - over 80% of the daily food intake should be hay.
A carefully balanced mix of veg (50g or less) and 1 tablespoon of pellets should be treated more in the way of a daily treat than the mainstay of the diet.
Daily exercise is also important. Rather than feeding treats, turn veg and pellet time into exercise and enrichment time; leave your boy only with hay for the rest of the time.
Please take the time to read these guides here; you will find them very helpful:
- Weight management including working out whether your piggy is overweight or not (heft) and how to best deal with overweight piggies:
Weight - Monitoring and Management
- Or detailed food guide, which looks at all food groups and also contains a picture of a recommended sample veg diet:
Long Term Balanced General And Special Needs Guinea Pig Diets
- Enrichment ideas to make food time fun time while you feed less:
Enrichment Ideas for Guinea Pigs
PS: Is Bailey a single piggy or does he company? Single piggies can become more food obsessed because of attention seeking and boredom.
Single Guinea Pigs - Challenges and Responsibilities