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Protein has many roles in your body.
It helps keep your immune system strong, repairs and builds your body’s tissues, transports and stores nutrients, and maintains proper fluid balance.
There are several advantages to following a diet high in protein, but there are also some concerns.
This article explains the benefits and risks of a high protein diet, foods to eat and avoid, and provides a sample high protein diet menu.
Protein functions and needs
Protein is one of the three macronutrients — the other two being carbs and fats — that your body requires in large amounts for normal growth and development.
They’re made up of long chains of amino acids linked together like beads on a string.
Your body needs protein to support the growth and maintenance of tissues, produce important hormones and enzymes, regulate normal fluid balance, and transport and store nutrients like cholesterol, vitamins, and minerals (1).
To support these functions, the dietary reference intake (DRI) is 0.36 grams of protein per pound (0.8 grams per kg) of body weight (1).
This amounts to 55 grams per day for a 150-pound (68–kg) adult.
However, the protein DRI is only the amount needed to prevent a deficiency — not what may be optimal for your activity level, physique goals, age, and health.
Benefits of a high protein diet
There are many benefits of a high protein diet.
A diet high in protein is beneficial for weight loss because it helps decrease hunger, increases metabolism, and reduces the loss of lean muscle mass.
Losing weight requires you to eat fewer calories than you need, which can increase hunger and make it more difficult to stay on track.
A high protein diet also increases metabolism because protein requires more energy to digest and absorb than carbs or fats (4).
Finally, eating a diet high in protein, especially in combination with resistance training, increases weight loss from fat rather than muscle (5).
For this reason, bodybuilders typically increase their protein intake to trim excess body fat but maintain their muscle mass during their cutting phase.
Improved blood sugar control
Protein is thought to have this effect by stimulating the production of insulin, the hormone that lowers blood sugar.
A high protein diet has also been shown to lower blood pressure and cholesterol levels in people with diabetes (8).
High blood pressure and cholesterol are risk factors for heart disease and kidney disease, conditions that people with diabetes are at increased risk for.
Exercise, especially weight lifting, causes micro-tears in muscle fibers.
Protein helps repair these micro-tears, building the muscle fibers back bigger and stronger.
In one study, female athletes who consumed a high protein diet and engaged in a weight lifting training program for eight weeks gained significantly more muscle and lost more fat than those who consumed a lower protein diet (9).
A daily protein intake in the range of 0.64–0.91 grams per pound (1.4–2.0 grams per kg) optimally supports muscle growth and recovery with exercise for most people (10).
However, some individuals may require higher protein intakes to support training and physique goals (11).
High protein diet risks
A high protein diet is safe and poses no health risks for the majority of people.
However, too much protein is rumored to be harmful to your kidneys and bones.
The kidneys play an important role in excreting waste products from the metabolism of protein in the urine.
As such, some people believe that eating too much protein makes the kidneys work harder, damaging them over time.
However, there is no evidence to suggest that a high protein diet causes harm in people with healthy kidneys (12).
For example, researchers found no harmful effects on liver or kidney function in people who consumed 0.91–1.37 grams per pound (2.0–3.0 grams per kg) of protein daily for longer than one year (13).
However, people with chronic kidney disease may benefit from eating a low protein diet to slow the kidney disease progression and delay the need for dialysis (14).
Some amino acids form acidic compounds in your blood.
These acidic compounds can cause your bones to release calcium to neutralize this acid, which is believed to contribute to osteoporosis or bone loss.
However, while protein can increase calcium losses, protein also enhances calcium absorption (15).
High protein diet foods
Many foods from both animals and plants contain protein.
While animal proteins have an amino acid profile that better supports muscle building, it’s best to consume a combination of animal and plant protein as each form offers different nutrients (18, 19, 20).
Animal protein sources:
- Poultry: eggs, chicken, turkey, duck, pheasant, etc.
- Dairy: milk, cheese, cottage cheese, and yogurt.
- Seafood: cod, crab, clams, salmon, scallops, shrimp, trout, tuna, etc.
- Meat: beef, lamb, and pork.
Plant protein sources:
- Nuts: almonds, cashews, pistachios, walnuts, etc.
- Seeds: flaxseeds, chia seeds, hemp seeds, pumpkin seeds, and sunflower seeds.
- Legumes: black beans, chickpeas, great northern beans, kidney beans, lima beans, navy beans, pinto beans, red beans, soybeans, peas, and peanuts.
Regardless of the protein sources, limit foods that are fried, highly processed, and prepackaged.
One-day sample high protein diet menu
Here is a one-day sample of a high protein diet menu.
Breakfast: scrambled eggs and oatmeal cooked with milk and topped with sliced strawberries
Snack: Greek yogurt and almonds
Lunch: oven-baked chicken breast, white rice, and broccolini
Snack: cottage cheese and fresh blueberries
Dinner: chili con carne with a baked sweet potato
While not always needed, protein supplements are a cost-effective and convenient way to increase your protein intake.
As a concentrated source of protein, these supplements are especially useful for people with high protein targets or who follow a low-calorie diet.
A simple whey protein like this one from Dymatize Nutrition offers 25 grams of high-quality protein per serving.
Whey protein is one of the two dairy proteins, the other being casein.
If you prefer a plant-based protein supplement, you can buy supplements made from pea protein, soy protein, rice protein, or a blend of different plant-based protein sources.
The bottom line
Following a high protein diet can aid weight loss, improve blood sugar control, and support muscle building.
There is no evidence to suggest that eating high amounts of protein damages your kidneys or leads to bone loss in healthy people.
Include a variety of minimally processed animal- and plant-based protein sources in your diet, including dairy, poultry, seafood, nuts, and legumes.
Protein supplements — while not always necessary — can help you meet your protein target.