Having lost a lot of weight by eating a healthy balanced low carb, low fat diet you will inevitably find that if you follow this lifestyle (yes, it is a lifestyle) - AND if you fall off the "healthy eating train" and have a high carb meal you will feel it. And not in a good way. Your digestive system upset/difficulty and your mood will be the immediate symptoms of a "not so healthy meal". It is simply your body telling you that processed, high fat, high carb foods are not good for you.
Processed sugar is the big one for me. Now if I have something high in sugar it really puts my body into something I call a defense mode. My stomach does not take well to PROCESSED sugars at all now, they upset my stomach and I feel uneasy right away after eating anything with processed sugars. Natural sugars (such as orange juice) in moderation are fine, but a sugary chocolate treat - forget it.
That being said, being diligent about eating correctly and using "food as fuel" and not "pleasure" takes a lot of will power. But I can say with conviction that eating many smaller, low carb, low fat meals/snacks a day is the way to a slimmer, happier, healthier, more rested, calmer, satisfied you. It is well worth the work and discipline. Good luck and enjoy.