Will eating healthy help me in the long run despite not losing weight?

For weight, it's all about calories.

800 calories of healthy food has 200 more calories than 600 calories of not-quite-so-healthy food and so would contribute more to your daily calorie intake.

This chart has some helpful advice:

Are you tracking your food? Weighing it all on a digital food scale? If you aren't then do that. You are probably underestimating food intake or overestimating your calorie burns or both and thus maintaining instead of losing.
You are going to lose weight if you have a calorie deficit. For weight loss calories is what matters.
You eat a particular way to meet your body's nutritional needs and to feel satisfied. It is a good idea to eat foods withots lf nutrients. Doesn't cause you to lose weight if you eat more calories.
If your sister weighs less and is maintaining it then she is eating fewer calories even though she is eating less nutritious food and less active.

You need to go into your goal settings on MFP and hit maintain weight, then check and see what the calorie sugestion is for maintaining your weight, after that slash 500 to 100 off the calories it says you need to maintain as long as it is not under 1200 per day. You should start losing weight after that!!

Will eating healthy be beneficial to you even if you don't lose? Sure, and I'll note that you are a healthy weight, even if not your ideal. If you were substantially overweight or obese reducing weight would be more of a priority.

You can lose if you want to, though -- just eat less of the overall healthy balanced diet (which I am assuming from your post that you have).

Relaxingmind wrote: »

What upsets me the most is my sister (who's the same height and only a couple years younger than me) is 115, slim, less active. She hates fruits, veggies, and meat unless the meat is fried or fast food. She eats ice cream or cookies every night and drinks juice or soda instead of water. And she doesn't track calories either. This doesn't seem right. Aren't the healthy foods supposed to make me slim and healthy, especially with me being active too?

No, healthy foods (or, more correctly, a healthy diet) doesn't make you slim -- how much you eat does. Many people will find that they just don't eat enough to gain weight so long as they focus on eating mostly nutrient dense foods or an overall healthful diet, but for many of us that's not enough. (Plenty of "healthy foods" also have lots of calories.)

I can maintain weight (at least around BMI 22) easily with such a diet and just being mindful of portions and being active, but I can easily gain weight if I stop being mindful of portions and it takes more work to lose (I'm 5'3 and 125 and would like to be a bit slimmer myself, or at least have lower body fat). It's just life. Focusing on your sister and her diet or things not being fair (nothing is ever "fair", I'm sure there are things about you where she thinks you have an advantage), is really not going to help you reach your goals or serve any positive purpose.

For the record, my sister is same height as me and was effortlessly (or so it seemed, it really wasn't) 110 for most of her life and is 115 now. I've been about 120 at my lowest and struggle with weight much more. Really, I'd still rather be me (because, you know, I am me). As for the diet thing not being fair, I don't see eating healthfully as a trade off, but a joy, and the benefits are much more than weight, but how I feel, overall long term health, so on. Don't think of it as a hardship (or if it seems so, change what you are doing).