weight

Question
We have 2 brother rats, Manny & Moe.  Manny has been losing weight recently and we finnally realized that Moe was stealing his food.  Moe is now quite hefty but Manny needs to gain weight.  Is there anything that we can do to help him to gain weight in a safe way?  I worry because I know that 1 day to him is years to me for health reasons.  

PS  I love your site!!

Answer
Do you leave food down all the time for them?

Thanks for the compliment about my site, but not sure which one you mean. Do you mean Critter City?
Because ALL experts is not my site, I just have been chosen to answer rat related questions but I have no authority here other than managing my questions/answers etc...