I don't know the answer to your question in the percentage way but I can offer some advice on amounts.
For carbs 50-75 g a day is considered an optimal level by Barry Groves. You can go up or down depending on dietary preference and individual needs of course. This should be based on lower glycaemic fruits and vegetables, avoiding sugars and starches and fruit juice.
For protein a minimum of 4 oz lean good quality protein three times a day has been found to prevent muscle loss(sarcopenia) in older people. We may or not be older people right now but we will be some day! The optimal level is 1.5 mg/kg protein a day based on your ideal weight. To calculate this take your ideal weight in kg. Divide this by 6. This is the total amount of lean protein in ounces that you should be eating over a day.
For fat, simply be careful about what fats you eat. Avoid unnatural fats and overheated /processed fats. Avoid deep fried foods, processed foods, vegetable oil and margarine. Eat the normal fat in animal products, butter, cheese, full fat dairy, coconut oil, macadamia nut oil, walnut oil. With fat use the amount that helps your food taste good. If you are losing too much weight up your protein and fat intakes.
My carb levels are 35-80g a day. Fruit tends to put my level up some days. My protein intake should be 12-20 oz a day. Despite being very carnivorous I am usually just over the 12 oz level most days.
I hope this helps.
Katharine.
