I want to thank Lastsyns for the time she took to Beta this story.
The Doctor watched his naked body in the mirror with a disgusted look. He hated it, every inch of this body. This regeneration of him was nothing like his old self. His old body was perfect. His old self wouldn't stand in front of his TARDIS mirror, grabbing the layers of skin. He could feel it, the fat. It was disgusting to him. There was a reason why he chose to not change his appearance when he got shot by a Dalek in front of Rose and Donna. It was all vanity, but no one knew.
He needed to stop adding sugar to his tea and cut down on fish custard. There wasn't much this body enjoyed eating. Almost everything he liked had a high level of sugar or was unhealthy in other ways. He enjoyed sugar, but the price wasn't worth it. Even if he spent most of the day running from an alien who wanted to kill him, it still didn't help him to burn the calories nearly as much as he needed.
He should have taken Amy's advice, that she had given him last time they met. He had went to pick them up but Rory was out of town for the weekend and Amy felt bad about leaving her husband behind. So instead they decided to just drink some tea and eat some cake in a café in the small town. She had warned him about what would happen to him if he ate the cake with whipped cream and the Jammie Dodgers. He had taken it as friendly teasing in the beginning but he was now starting to see what she had been warning him about. Even if he were a Time Lord sugar was still bad for him. The difference between humans and Time Lords in the matter was that Time Lords had more control over their cravings, which this body of him had failed miserably in. But he could do it, for Jack.
Even if Jack told him it didn't matter how he looked, he still knew Jack preferred his old body. He didn't blame Jack, he himself preferred his old body. He could eat everything he wanted without having to worry about gaining weight. This body was different, he needed to be cautious of what he was eating. Which wouldn't be a problem if it wasn't for his irresponsible choice of foods.
It was Jack that made him really think about his weight. Jack had prepared a perfect date in his apartment where the Doctor was living from time to time. Jack had picked him up in his strong arms to carry him to the bedroom when Jack said something that had changed his life. The words echoed in his head in an endless replay. "Wow Doc, someone has gained weight since your last body. I think soon it will be you who will need to carry me"
He hadn't really enjoyed Jack's loving during the night. He was thinking about how horrible he must look for everybody to comment on his weight. He was used to everybody telling him how slim he was, not how fat he was. It was really getting to him. Jack really thought he was too heavy, that would explain why he had given him low-fat milk and no sugar to his tea this morning. He had even been given a banana which must be a hint for him to cut back on his Jammie Dodgers.
His pants had been ripped apart the last morning when he had sat down with Jack to keep him company during breakfast. Jack had of course been quick to tell him how his unhealthy choice of food started to show. He doubted it was a joke, even if the other man was laughing. He was of course laughing at him. He knew he couldn't keep Jack if he didn't do something about the matter.
He was trying to see if he could fit in his old body's pinstriped suit. He usually never put on his old clothes, but now he needed to see just how out of control he was. The answer made him sick, he was very out of control.
He would just have used Jack's gun to regenerate, if this wasn't his last body. He didn't want to leave Jack, but he still wanted to give Jack more than he could give him. He never told him that this was his last form. He didn't dare to give him the bad news. Jack was happy to have found someone he could live a long happy life with. It would be long, but not as joyful as Jack imagine. He didn't want to take away Jack's happiness, but he needed to do it sooner or later.
The Doctor's stomach was burning because of his hunger but he couldn't give up now. He had already cleared three days with just drinking plain tea once a day and water to not dehydrate. He wasn't weak, just hungry and in a bad mood when someone talked to him. It was hard for him to not go to Jack's kitchen to search for something to eat in the fridge when he left his TARDIS that was parked inside Jack's living room. He tried to stop thinking about how great a raspberry and rhubarb pie would taste as he walked in to Jack's bed room. He undressed himself and laid himself next to the human's strong body. He always felt safe in his arms. He lay just thinking for a while when he finally decided to ask Jack what he really thought.
"Jack, are you asleep" he asked as he turned to Jack to see if he heard him.
"Almost, can't sleep?" Jack's beautiful eyes were closed. He wanted to see them but he didn't want to disturb the other man more than necessary. He would soon go to work during the day.
"Do you think I'm too heavy?" It was quiet for a while until he heard Jack move and felt his arms around his disgusting body. He knew the human were half asleep but was still trying to comfort him.
"Yes." It didn't matter if Jack knew what he was saying. He knew Jack was right.