Always this same bullshit lol
Okay let's say Abby has access to high quality sources of food so she can stick to her perfectly balanced fitness diet for years.
Eating and training don't lead to muscle growth. The equation goes eating + training + rest = muscle growth.
The zombie Apocalypse is not the perfect place to keep your stress levels low in order to get 8 hours of sleep every night.
Growing muscles requires you to stimulate your muscle fibres to failure. Let's say she does pullups to reach a higher place. And she has, for whatever reason, to do so many pullups in a short amount of time (less than 10 secs between pullups), that she creates a hypertrophic stimulus in her back and biceps muscles. The moment she keeps going on and puts more stress on her biceps and back, she will not grow any muscle because the muscle protein breakdown is too severe. "Going on" here even means the next day.
If you sprint away from a zombie and you do so, for whatever reason, in a HIIT training style and get proper rest (48-72 hours) afterwards, you will grow muscles in your legs. But if you do it everyday without steroids, you will not grow muscles. You will lose them.
You can't grow muscles without getting fatter. Even with steroids it's almost impossible for men who have a much higher anabolic potential. So in order to become jacked Abby, she would have to go through multiple cycles of bulking (caloric surplus) and cutting (caloric deficit). These fitness cycles are unnatural. They are a dumb thing to do as they put you in a big disadvantage for survival. During a bulk, Abby would have reduced cardiovascular performance and overall fitness. During a cut, Abby would have reduced regeneration capabilities, much higher stress levels and less peak physical and mental performance. Putting yourself through this just to be remembered as jacked Abby is stupid.
Also keep in mind that the female body can't endure as much stress as the male body. While the female body has great advantages like a premium immune system with surplus capacities for cases of pregnancy, it reacts really badly to high levels of physical stress. Women need more regeneration than men. If you see a woman with abs, you can bet your ass that she sacrificed her period to look like this. The female body is not built to work under low bodyfat levels and many female fitness models use steroids like Anavar and plastic surgery to reach their low bodyfat looks.
In a zombie apocalypse, no one would be jacked. Not even the males. Everyone would look like a marathon runner because that's what long term physical and mental stress does to your body.
The stupid thing about Abby is, that even if she has access to high quality food, in order to make this crap work, she would have to have this access exclusively. She looks like She-Hulk while everyone else is just normal? Sorry but that's shitty writing. TLOU2 is shitty writing.