How Much Protein, Fat, Carbohydrates and Fiber Should Each Meal Have?

Eating a "balanced diet" is something we all know we should do. But what that looks like in any given meal can be much less obvious.

Recommendations on which types of food, and in what amounts, we should be eating seem to change based on who you're talking to. Even the traditional gold standard, the USDA Food Pyramid, has been rejiggered over the years.

That said, getting the right amount of macronutrients — including protein, carbohydrates, fiber and fat — in your daily meals is important. "Each macronutrient has a role in the body, and missing out on one affects how we function," says Adrien Paczosa, RD, LD, CEDRD-S, chief clinical officer at Nourish, a national nutrition group.

Here's what you need to know to get it all down pat.

Proteins help the body heal itself, explains Paczosa. According to The National Academy of Medicine (NAM), adult women need about 46 grams of protein per day, and adult men need about 56 grams, which translates to 15 to 19 grams of protein in each of your three meals.

Those figures are based on a recommendation of 0.8 grams of protein per kilogram of body weight, though, which makes them accurate for women who weigh about 125 pounds and men who weigh about 155 pounds. If you weigh more, you probably need more protein.

You are also likely to need more than that if you are especially active. A paper by British sports scientists at the University of Stirling recommends that track and field athletes intending to build muscle mass eat around 1.6 grams per kilogram (2.2 pounds) of body mass each day. Using this formula, a 125-pound woman would need about 90 grams of protein daily. (If that seems a bit high for your activity level, talk to your doctor or a registered dietitian about what amount might work best for you.) For reference, a scoop of protein powder delivers about 10 to 30 grams of protein depending on the brand, according to Harvard Health Publishing, while one cup of grilled, diced chicken breast has 35 grams, according to the USDA.

‌Read more:‌ Here's What Serving Sizes of Meat and Seafood Actually Look Like

"The poor misunderstood carbohydrate!" laments Paczosa. "It is the body's preferred source of energy." She insists that carbs shouldn't be avoided. "They fuel your body and brain so you feel your best," she says.

NAM has the same daily carbohydrate recommendation for men and women: 130 grams, which works out to about 43 grams per meal. Paczosa's advice falls in line with that. She notes that a serving of carbohydrate is 15 grams and she encourages her clients to include three servings at most meals, depending on their activity level and medical history. "When I work with clients, we determine the ideal servings for their individual goals." (One slice of whole-wheat bread has about 14 grams of carbs, and a large banana has 31 grams.)

Fiber piggybacks into your diet with your carbohydrate sources, including whole grains, fruit, beans, and veggies. NAM suggests that men up to age 50 get 38 grams of fiber daily, which is about 13 grams per meal. Older men should aim for 30 grams daily, or about 10 grams per meal.

For women younger than 50, the recommendations are 25 grams daily; for women older than 50, it's 21 grams daily, or about 7 to 9 grams per meal. To put that in perspective, a bowl of oatmeal made with a half cup of dry oats has about 4 grams of fiber, while one cup of canned kidney beans boasts 13.5 grams.

Eating healthy fats keeps you feeling full and helps your body absorb essential vitamins and minerals. NAM suggests that healthy men and women get between 20 and 35 grams of total fat per day, which is a range of about 7 to 12 grams per meal.

To avoid raising your risk of cardiovascular problems, eat mostly unsaturated fats, such as nuts, seeds, avocados, olive oil and fish. A 3-ounce serving of wild-caught salmon has 7 grams of fat, and a tablespoon of olive oil equals 13.5 grams.

‌Read more:‌ Your Ultimate Guide to Fats and Why Your Diet Needs Them

Before you revamp your meals, it's smart to check in with your doctor. While general guidelines are a solid starting point, what ‌your‌ body needs may hinge to some extent on your age, sex, weight, physical activity level or other factors. Your doctor can provide the big-picture perspective that will enable you to fine-tune your new healthy meal plans.