I am (usually) vegan and I feel great.
My favorite trick in the whole world is to keep baby greens on hand. I love arugula. I make my own dressings with oil and vinegar or tahini and olive oil. So easy. Then I cook brown rice and quinoa twice a week in a rice cooker, and then I do the same with lentils, chick peas and black beans. Sometimes I just buy these in cans, without the preservatives. Also, mushrooms, corn and peas. So all of the cooking/prep I do for these salads happens once or twice a week and takes well under an hour (the rice cooker works in 45 minutes). I keep all of these in separate glass jars for mixing-and matching in the fridge. I also have some nuts and seeds on hand. I refill them as necessary, which is usually just the once a week.
Whenever I'm hungry in the afternoon, I always make a bowl of salad first with the grains on the bottom and a bit of beans/veggies on top. It takes 30-60 seconds, on the spot. Afterwards, I'm not panicked by hunger and I can make better choices about whether I need anything else, and what that should be. Because of all the easy options, I never get sick of the salad! But when I'm finished with the smallish salad, I can make up my mind about what else my body needs. Usually I cut up a mango or avocado, or have a handful of nuts.
It's hard for me to listen well to my body when I'm starving. When I have a plan to stave off hunger as it comes up, I make better decisions about what else I need, if anything.
This is a fantastic, whole-foods-focused way for me to eat. Since I've done this, my health and sense of energy has changed dramatically.
I like making green smoothies in the morning, too, but not everybody is into that.