A: The number of grams of protein one should eat depends on a number of factors. The most important of these are your bodyweight and whether you are trying to gain muscle or lose fat.
While trying to gain muscle (i.e. you are eating a surplus of calories each day), eating 1-1.25 g of protein per pound of bodyweight is ideal. A 200 lb man would need between 200-250 g of protein per day.
When trying to lose fat (caloric deficit), that number should increase to 1.5-2 g per pound of bodyweight. That same 200 lb man would now need to eat 300-400 g of protein per day.
There are 3 reasons for eating more protein on a reduced calorie diet:
- Eating more protein will ensure that there are enough amino acids available to maintain muscle mass while dieting. When you are eating more calories, you don't have to worry about losing muscle mass because your caloric needs are covered.
- Protein has a higher thermic effect of feeding than either carbs or fats. This means it costs your body more energy to process and use protein. Since we are trying to burn more calories, this is a good thing.
- Most people will see better results from eating more protein and dropping carbohydrates fairly low when trying to lose bodyfat. This inhibits insulin secretion (important because insulin is a storage hormone; it makes the body want to store fat, not burn it), keeps blood sugar levels more stable (important for reducing or eliminating cravings), and reduces water retention (which is why everyone loses 5-10 lbs in the first few days of a low carb diet). To accomplish this, you have to increase protein and fat intake so that you do not decrease calories too much.
So, I have to answer the question with a question: Are you following the 5 Simple Rules at least 90% of the time? Are you tracking your compliance, or just winging it? You have to crawl before you can run, so if you still don't have the basics down, worrying about advanced things like how much and when on what day is like trying to race in the Indy 500 before you pass your driver's test.
Instead of worrying about small details like how many grams to eat, just focus on the 5 Rules. Every day that you follow them to the letter for the day, put an X on the calendar. If, at the end of the next month, you see a lot of blank squares (more than 3), then you have some work to do mastering the basics. If you see a wall of Xs, then you can think about moving on to more advanced nutrition.
Master the basics. They are all that most people will ever need to see great results.