Everything you say about how you feel and what you eat points to, like most people here, your diet is too high in fat and animal protein. Feeling the need to eat something salty and greasy is a sign you haven't eaten enough that day and your body is craving more calories.
See how many calories you're eating a day on average and, just as importantly, what your macro nutrient ratio is which you'll find on the bottom right of the app as a colored pie chart showing protein/carbs/fats.