Protein calculator

What protein does in your body

Protein is one of the three main nutrients in food, along with carbohydrate and fat. Your body breaks it down into amino acids and uses them as building blocks. Muscle, skin, hair, bones, enzymes, some hormones and parts of your immune system all depend on a steady supply.

Your body is always breaking down and rebuilding its own proteins. Eating enough protein, and giving your muscles a reason to adapt through exercise, tips that balance toward keeping or adding muscle. Protein also tends to be filling, which many people find helpful when they're trying to eat a little less.

Unlike fat, your body doesn't keep a large store of spare protein for later. That's one reason it makes sense to eat some every day, and ideally at most meals.

The ranges behind the calculator

The calculator multiplies your body weight in kilograms by a range that matches your situation. If you enter pounds, it converts first (1 kg is about 2.2 lb). These are the ranges it uses, in grams of protein per kilogram of body weight per day:

• Mostly inactive adult: 0.8 g/kg. This is the Recommended Dietary Allowance (RDA), the amount that covers basic needs for nearly all healthy adults. Think of it as a minimum, not an ideal.
• Age 65 and over, not training regularly: 1.0–1.2 g/kg. Expert groups on aging suggest older adults aim somewhat higher than the RDA to help hold on to muscle.
• Exercise regularly: 1.2–1.6 g/kg. A common range in sports nutrition guidance for people doing cardio, team sports or general fitness.
• Strength training to build muscle: 1.6–2.2 g/kg. From the International Society of Sports Nutrition (ISSN) position stand. Research suggests the extra benefit for muscle gain tends to level off around 1.6 g/kg, so the upper end is a margin rather than a requirement.
• Losing fat while strength training: 1.8–2.2 g/kg. The higher end, to help you keep muscle while you're eating fewer calories.

Worked example

Someone who weighs 80 kg and lifts weights three times a week: 80 × 1.6 = 128 g up to 80 × 2.2 = 176 g a day. Across four meals, that's about 32–44 g per meal: roughly a chicken breast, or a bowl of Greek yogurt with a scoop of nuts and seeds.

If those numbers look high compared with what you eat now, start at the low end of your range and build up over a few weeks.

Spreading protein across your meals

The total you eat over the day matters most. Still, it's easier to eat 30 grams four times than 120 grams at dinner, and some research suggests muscle responds a little better when protein is spread fairly evenly. A simple approach:

1. Divide your daily target by the number of meals you usually eat. The calculator does this for you.
2. Build each meal around one main protein food, then add vegetables, grains or fruit.
3. Check breakfast. It's often the lowest-protein meal, so eggs, yogurt or cottage cheese there can close much of the gap.
4. Use snacks to fill whatever is left.

Getting there with food

Most people can reach these targets with ordinary food. Lean meat, fish, eggs, dairy, tofu, tempeh, beans and lentils all help, and spreading protein across meals is easier than eating it all at dinner. For a full list of foods and their approximate protein content, read how much protein you need per day.

Some everyday examples, with rough amounts (exact numbers vary by brand and preparation):

• About 100 g (3.5 oz) of cooked chicken breast: around 30 g of protein
• One can of tuna, drained: roughly 25 g
• A 170 g (6 oz) pot of plain Greek yogurt: about 15–18 g
• Half a cup of cottage cheese: about 12–14 g
• Two large eggs: about 12 g
• One cup of cooked lentils: about 18 g
• 100 g of firm tofu: roughly 12–17 g, depending on how firm it is
• One cup of milk or soy milk: about 7–8 g

Put a few of these together and the numbers add up quickly. Eggs and yogurt at breakfast, a tuna or lentil salad at lunch, chicken or tofu at dinner, and cottage cheese or milk as a snack adds up to roughly 100 grams, before counting the smaller amounts in bread, grains, beans and nuts. No special products needed.

If you eat a plant-based diet

You can meet your protein needs without animal foods. A few things make it easier:

• Eat a variety of protein sources across the day, such as soy foods, beans, lentils, peas, whole grains, nuts and seeds. You don't need to combine specific foods at every meal, as long as the day as a whole is varied.
• Lean on soy foods like tofu, tempeh, edamame and soy milk. They're among the most protein-dense plant options.
• Consider aiming toward the middle or upper part of your range. Some plant proteins are digested a little less completely than animal proteins, so a bit of extra margin helps.

Common protein myths

"Your body can only use 30 grams per meal"

Your body digests and absorbs nearly all the protein you eat, whether the meal has 20 grams or 60. The 30-gram idea comes from studies that measured short-term muscle building after a single dose, where the response seemed to level off around 20 to 40 grams. More recent research suggests larger servings may still be put to use over a longer stretch of time. Spreading protein out is a sensible habit, but a bigger protein meal isn't wasted.

"More protein always means more muscle"

Protein supports muscle growth, but training is what drives it. Past roughly 1.6 g/kg, extra protein seems to add little for most people. A consistent program that gets gradually harder matters more. See progressive overload explained and the beginner strength training plan for where to start, and use the one-rep max calculator to set your training weights.

"High-protein diets damage your kidneys"

In healthy adults, research hasn't shown harm from intakes in the ranges this calculator uses. That's different if your kidneys already don't work normally, which is covered below.

Who should check with a professional first

These ranges are for generally healthy adults. Talk to your doctor or a registered dietitian before raising your protein intake if any of these apply:

• Kidney disease or reduced kidney function. People with chronic kidney disease are often advised to limit protein, sometimes below the RDA. Follow your care team's guidance rather than this calculator.
• Liver disease, diabetes with kidney complications, or other chronic conditions that affect how you process food.
• Pregnancy or breastfeeding, when needs rise and should be planned with your care provider.
• Teens and children, whose needs are based on growth and are set differently from adult ranges.
• Older adults with health conditions or reduced appetite, who may benefit from a plan tailored to their health and medications.

Whatever your target, keep eating plenty of vegetables, fruit and whole grains. Fiber often drops when people focus heavily on protein.

How protein fits with your calories

Protein is only part of the picture: total calories still decide whether you gain or lose weight. The calorie calculator gives you that number.

Each gram of protein has about 4 calories, so 130 grams is around 520 calories. That leaves room for carbohydrate and fat, which fuel your training and help you absorb important nutrients. If you're cutting calories, keeping protein steady while trimming elsewhere helps protect muscle. For recovering well between sessions, read sleep and recovery for training.

Based on: International Society of Sports Nutrition position stand (2017) and the Recommended Dietary Allowance.