Trying to determine how much protein you need can feel like trying to solve a complex algebraic equation with multiple changing variables: What is your age? What are your goals? What is your activity level? Each person has unique needs and responds to inputs differently; the amount of protein you should eat depends on so many factors, there could never be a one-size-fits-all prescription.

There are, however, two effective ways of calculating how much protein you should be eating in a day, and both are good starting points for anyone looking to optimize their diet. One focuses on minimal requirements, while the other sets targets based on fitness goals. Read on to learn how to calculate your intake based on your body type, needs, and goals, as well as the best foods for meeting your protein requirements.

Protein: What Is It Good For?

As the major building block of the human body, protein builds and maintains your organs, muscles, tissues, and hormones. It’s involved in nearly every bodily function and is necessary for survival.

When eaten in appropriate amounts, it also confers significant health benefits beyond mere survival. Since it works to build and repair muscle, it helps you maintain and lose weight, and can also limit muscle soreness after a workout. It helps you feel full after a meal and stabilizes your blood sugar — two important factors when looking to achieve or maintain a healthy weight.

Because your body expends more energy to process protein than carbohydrates and fats, you also use up more of the calories you’re consuming just to absorb them. This is called thermogenesis, and it’s another way protein intake aids weight loss.

Ways to Calculate How Much Protein You Need

By Body Weight

The standard Recommended Dietary Allowance (RDA) for protein intake has, for years, been 0.36 grams per pound of body weight. A 200-pound, sedentary man, for instance, would require 72 grams of protein per day. Think of this as his baseline. It’s the minimum amount of protein he would need to meet basic nutritional requirements — and this calculation works for men and women alike.

If you’re an office worker who rarely exercises, you really don’t need more protein than this. Taking in more could be doing more harm than good. Protein is a great fuel if you’re using it but if you’re not, it just gets stored as fat and potentially puts you at risk for metabolic disease. Your body needs to use more water to flush out the extra nitrogen that protein releases into your body. An overabundance of protein can lead to dehydration, constipation, and kidney stones.

If you’re getting in at least 30 to 40 minutes of moderate exercise four or five times a week, however, you’ll want to make some adjustments. This is even truer if your workout includes resistance training. Nancy Rodriguez, a professor of nutritional sciences at the University of Connecticut, suggests increasing your protein to 0.5 to 0.9 grams per pound of body weight each day if you’re an active person. The more resistance training you do, the higher you’ll want to be in that range.

Don’t feel like doing the math yourself? There are plenty of calculators online: check out this one from Global RPH or this one, which was originally developed for bodybuilders. A good one will take into account your gender, weight, activity level, and age — remember, growing children and teens need more protein than adults.

By Percentage of Total Calories

There’s another method for calculating how much protein you should eat, and that’s by setting macronutrient ratios. Favored primarily by fitness professionals, this method uses fitness goals to determine the ideal ratio of protein, carbohydrates, and fat you should be eating in a day. It also takes into account whether you’re working to gain muscle, lose fat, or maintain a healthy weight, while considering specific body type — endomorph, ectomorph, or mesomorph.

If you’re looking to build muscle, or you’re an endurance athlete, you’ll want to consume more carbohydrates and less fat. Here’s a breakdown for those who are looking to build muscle:

Carbs: 40-60% of daily calories
Protein: 25-35% of daily calories
Fat: 15-25% of daily calories

If you just want to maintain your weight, your macros might look something like this:

Carbs: 30-50% of daily calories
Protein: 25-35% of daily calories
Fat: 25-35% of daily calories

And if fat loss is your goal, you should strive for more protein and fat, and fewer carbs. Those wanting to shed pounds can follow this guide:

Carbs: 10-30% of daily calories
Protein: 40-50% of daily calories
Fat: 30-40% of daily calories

So, if you know you need to eat 2,000 calories a day to put on muscle, you’d want perhaps 50% of your calories to come from carbohydrates, 30% from protein, and 20% from fat. That translates to 250 grams of carbs per day, 150 grams of protein per day, and 44 grams of fat per day.

What to Consume and When

Ideally, you should have a modest portion of protein at every meal. If you need 80 grams of protein per day, you might choose to have 20 grams at each meal and divide the remaining 20 amongst your snacks, or in a post-workout shake. This way, you stay fueled throughout the day and stave off cravings for less healthy foods.

It’s important to consider a food’s protein content in relation to other nutrients. Something that’s high in protein but also contains lots of sugar, like many energy bars, isn’t the best choice — not to mention, consuming empty sugar calories leaves less room in your diet for more nutritious, vitamin-rich foods.

Lean meats and lower-fat dairy, beans and legumes, nuts and seeds, whole grains, and certain vegetables all contain protein. When combined, they form the basis of a nutritionally complete and diverse diet. That said, it’s not always easy to eat properly on-the-go or if you have dietary restrictions, so it’s worth considering protein powders as a handy alternative.

Protein powders and shakes can be a life-saver, especially for highly active individuals and for vegans and vegetarians. While there are plenty of excellent plant-based sources of protein, it can sometimes be a challenge to meet your requirements without overloading on carbs or fats at the same time, so don’t overlook these as a viable option.

Top Protein Sources

Chicken (white meat): 35g per 4oz serving
Cottage Cheese: 25g per cup
Greek Yogurt: 10g per ½ cup
Eggs: 6g per large
Canned Tuna: 26g per 4oz
Wild Salmon: 26g per 3.5oz
Black Beans: 15g per 1 cup, cooked
Lentils: 9g per ½ cup, cooked
Black Rice: 10g per ¼ cup, uncooked
Peanut Butter: 4g per tablespoon
Tempeh: 16g per ½ cup
Tofu: 10g per ½ cup
Oats: 6g per cup
Brussels Sprouts: 2g per ½ cup

It Doesn’t Have to Be Complicated

While the amount of protein needed is an admittedly complex topic, knowing how to determine what’s right for you is more than half the battle. It all comes down to goals and lifestyle. Once you’ve identified these two pieces, you can start to build a simple outline for your daily meals.

Author's Bio: 

Katie Di Lauro is a registered dietitian nutritionist at Tri-City Medical Center, a full-service, acute-care hospital located in Oceanside, California. Katie has over 14 years of experience in the wellness industry as an individual and corporate wellness educator and is truly passionate about wellness and helping her clients achieve their goals through education, motivation, and accountability.