I've read time and time again that it is important to eat within an hour of lifting/strength training in order to maintain lean muscle mass...but if I'm not hungry, and if my goal is to ultimately lose fat (about ten pounds), do I need to eat within a certain window following a 40-minute strength training session? I'm a twenty something female...
It depends on how well your body recovers after a heavy lifting session. If your completely wiped and body aches all day and night then yes i would eat. If you feel fine then don't waiste the calories. Let your body tell you what you need. My $.02
I'm a fan of eating only when hungry. The sensation of hunger evolved over millions of years and is pretty reliable - except when you break it by eating when you're not hungry and eating poorly.
My understanding is that it is good to refill glycogen in the muscles after workout, and a natural way to do it is to eat some carbs after workout. The question is, whether your training is so intense that such optimization would matter. It's probably enough to just eat when hungry.
Just one idea to think about: I don't know how typical is my evidence, but I found out that my weight is going down effortlessly when I just eat proper paleo food + going low carb. First I did walking + strength training, later I switched to walking only, and in the last weeks I do just very little walking and nothing else. And still, in my case, my weight is still going down when I eat low carb... what I want to say is that workouts are good, especially when you enjoy them, but still... if your primary goal is weight loss, I would focus on eating quality protein+fat and limit carbs.
You need to eat protein before or after exercise so not to loose muscle, but you need to omit carbs if you can. If you are not hungry still get 1 shake of 20g protein.
I don't think you need to eat in certain window if you are not taking carbs. If you are taking carbs, its best to eat them at most 1 hour after exercise as it will produce no harm then, as muscles will soak them up ASAP. Contrary to that, if you don't eat carbs ASAP after exercise you aim at slower regeneration of muscles so you need to pace yourself. Remember, you differ from body building nuts - you don't want muscle hypertrophy like crazy, you want to reverse adipose hyperplasia.
I recommend eating after heavy lifting as you do not want your body to lose muscle. That being said how "hard" are you lifting? Also if you are not taking in too many carbs, and not depleting your glycogen reserves (ie. crossfit workout) it is not that big a deal in terms of the timing.
I know from personal experience that lifting should increase your appetite. Not necessarily directly after, but in general. It really depends on the type of workout.
On the days you don't lift is when I would try to cut back a bit. Also I have more fat on non workout days, and a bit more carbs on the lifting days. That has worked pretty well for me in terms of keeping muscle and losing fat.
But I agree that if fat loss is your only goal, then don't worry about the timing. Eat when hungry or try IF.