Snickers prefers the fruity pellets (Zupreem). I know there are healthier pelleted diets available, but since it's not his main meal - I just view them as treats (or something to snack on between healthier meals). I think it would be difficult to interest him in 'all-one-colour-healthier' pellets. I may be wrong. If his main diet was pelleted, I would probably mix pellet types.
Hope your guy starts becoming more adventurous in trying new foods.
Perhaps you could eat such stuff around him (like really in his personal space) and deliberately NOT share -- esp since they always want they can't have? Like a big production of eating around him, letting him have a sniff and then pulling dish back away from him? Force him to steal a bite? I dunno -- these greys are so smart, he might not fall for it anyway. lol