When adapting to a new diet, a common challenge is serving size. Am I eating too much? Not enough? How do I know how many calories are in the foods without labels?
You think: "There's no labels on my banana listing the calories, sugars, fat, fibre..so maybe I should skip it."
Wouldn't it be nice if there were labels and evenly portioned foods done for us without the mystery? One option is to do research, buy a food scale and weigh everything according to grams. I myself have never used a food scale before. I would rather not weigh all of my meals and not bring it along with me in my purse.
So now, you ask what DO I do to eliminate this constant anxiety of the unknown? First, if it has a label, READ IT! See how it fits with your plan. If the serving size seems like barely any food to keep you satisfied then don't have it. The worst feeling is when you feel like a bird eating your meal. Next, if this food fits in with your diet, portion it into smaller bags ahead of time to eliminate stress (ie almonds). If it is a bulk item like oatmeal, I keep the 1/3 cup measuring cup in the bag so I can use it as a scoop every morning.
For items without labels like chicken, I will either compare my chicken to a labelled portion chicken and use something like the palm my hand to remember how big one piece was. So when I buy my own in a package I don't have to weigh 100grams and can cut it into smaller servings. If it is something like fruit, I look it up! Then roughly portion it. With things like nut butters and jams, I measure it once with a tsp/tbsp and see how it fits on my normal spoon. Then I know for the future how much to fill my spoon. Using the same bowl/plate for items works well too. I know my egg white serving in the morning fills a small dessert bowl I have
so I microwave it in that bowl every morning!
At first, some of these things may seem to take some effort and time, but after awhile you will know automatically what size different foods should be. Myself, I would not be sane measuring my food for every meal so these things work for me! Find what eases your mind and fits into your life the best :) Eating healthy should be a fun experience, not a dreadful one!