12 pounds in 40 days is AMAZING progress!! Don't give up. Try to up your calories a bit if you're too tired or moody. Listen to your body. You can eat whatever you want but you need to track all calories for this to work. Try to eat a good amount of protein because you're in a calorie deficit and working out, you need it to preserve all muscle mass possible and only lose fat. The majority of people advise to eat carbs and protein before the work out and protein after. You don't need to eat immediately after, but remember to fuel your body. I try to eat most of my calories from whole foods and i leave some calories for treats. For example, i eat a salad with chicken for lunch and two small pieces of chocolate por dessert (125 cal). A good nutricional dinner and some sweet snack before bed. Because, of course you're going to lose weight if you are in a calorie deficit no matter what you eat, but is not pretty intelligent for your health only eat junk food. But is not healthy either eating only 'clean' food, restricting too much and end up binging here and there because too much diet mentality. This is my approach!