I am trying to work out how much fat, carbs, and protein I should be consuming daily based on my BMR which is around 2025 calories. Apparently you're supposed to have 500 calories less than your BMR to lose around 1lbs a week.

Anyway, I have done the following calculations and wanted to know if I have worked it out correctly:

type        percentages     calories    grams per calorie   grams

fat          30              457.50     9                    50.83
protein      15              228.75     4                    57.19
carbs        55              838.75     4                   209.69

calories    100             1525.00

Have I worked this out correctly? Does this mean I should be having around 317g of food a day?

2 Answers 2


You want to have enough protein to protect your muscles. This is more important than carbs and fat. To find out how much protein you need, you can use the calculator over here. While it's more accurate to use your lean body mass, it won't hurt you to calculate based on your overall body weight--you might even increase your muscle mass that way.

  • Try not to over-think your diet. If it's too hard you'll give up.
  • Make sure you have the protein you need.
  • Make sure to eat plenty of veggies (two servings each for lunch and dinner)
  • Make sure to drink plenty of water (minimum of 2L/day)
  • Make sure you have at lest 21g of dietary fiber a day (up to 40g if you need it)
  • Include small doses of healthy fats (like 30-60ml of olive oil)
  • You'll need a multivitamin, and omega-3 supplements would be nice.

If you have any calories left after your protein and veggies, you can spend them on the things you like. Don't worry too much about the fat to calorie ratio. You'll find that at ~1500 calories you won't have much room for too much of that anyway. NOTE: some people are sensitive to glutens or dairy and tend to hold on to their weight more when they have foods rich in those.

Keep a food diary/weight journal and review it weekly. Also take your measurements at least monthly. If you have a bad weight loss week, double-check your measurements. My wife recently had a 0 weight loss week but lost 15cm overall. If you still aren't happy, look at the types of food you are eating. You may have to adjust it for what your body processes better.

Some veggies pack a one-two punch like Spinach. Spinach gives you about 4g fiber per serving and even has some protein in it.

Also, exercise increases the amount of calories you burn in a day. Anything you do to increase your muscle mass will also increase your BMR. The combination of having higher amounts of protein (meaning 0.5g protein/Kg lean body weight) and exercise will improve your muscle mass. If you walk on a treadmill for an hour you can burn around 400+ Calories. That means you could have 1900 calories on your exercise day and still be on target to lose 1 lb a week.

  • Thanks. Looks like I should be having about 65g of protein. If protein is the most important, what is the next most important out of carbohydrates, fat, and fiber? Also, are they the 4 basic requirements I should be looking at, i.e. protein, fat, carbs, fiber + water and vitamin and omega-3 supplements? Commented May 4, 2011 at 13:41
  • The importance should be protein, veggies, fiber. Fat and carbs are about equal and at the bottom of the list. So yes, look at protein, fiber, water, vitamins and omega-3s, fats, and carbs. Favor real food over the "sugar free" or "fat free" varieties, and favor complex carbs over simple ones (i.e. brown rice is better than cane sugar). Fat free food tends to compensate by adding lots of carbs, and sugar free foods tend to use man-made sugar replacements or compensate with fat. Commented May 4, 2011 at 13:59
  • Another thought, think of protein in terms of "at least" and fat/carbs in terms of "at most". Your brain is the only organ in the body that requires blood sugar to operate (i.e. carbs). It only uses about 100g of carbs a day. Anything in excess of that isn't going to help matters. Also, it takes 6 hours for your body to switch from burning carbs to burning fat. If you only do carbs at breakfast and dinner, you will give your body a chance to burn some fat at least twice a day (one of them while you are sleeping). Commented May 4, 2011 at 14:03

No, that does not mean that you should only be eating 317 grams of food per day.

Not all food is digested, and not all food matter has energy value to the body. For example, cream cheese has about 3.5 calories per gram, while broccoli has around 1/3 calorie per gram (according to www.thecaloriecounter.com). Vegetables in particular are ridiculously low-density in calories for human beings, since we can't digest cellulose, the major component of plant cell walls (which is about 1/3 of plant matter, according to Wikipedia).

  • OK, so basically, I should be having 50g of fat, 57g of protein, and 210g of carbohydrates daily to make up my 1525 daily calorie intake? Commented May 4, 2011 at 9:02
  • 1
    @oshirowanen: I wouldn't exactly say that. Diet is a complicated subject and I'm not trying to cover it here. But if you were aiming for the 30-15-55 proportions that you describe in your question, then the 50/57/210g amounts are what you'd aim for using nutritional data from labels, etc. The main point is that 100g of food does not split neatly into protein, carbohydrate, and fat with nothing left over.
    – jprete
    Commented May 4, 2011 at 13:42

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