If you’re on a low-protein diet, try eating more grains, fruits, and vegetables and cutting out animal products. But eating only low-protein foods can lead to nutritional deficiencies and should only be done with medical supervision.

A low-protein diet is often recommended to help treat certain health conditions.

Impaired liver function, kidney disease or disorders that interfere with protein metabolism are some of the most common conditions that may require a low-protein diet.

In recent years, some research has also found that low-protein diets may extend longevity and offer protection from chronic disease.

This article looks at the pros and cons of a low-protein diet and whether you should start reducing your protein intake.

What Is a Low-Protein Diet?

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A low-protein diet requires you to restrict the amount of protein you consume, typically so that it constitutes 4–8% of your daily calories.

This translates to somewhere between 20–50 grams of protein per day, depending on how many calories you consume.

For comparison, the average person is generally recommended to get at least 10–15% of their daily calories from protein. This amount may increase for athletes, older adults and those with certain health problems (1).

Protein is vital to health, but reducing protein intake can be therapeutic for people with specific conditions.

In particular, low-protein diets may benefit those with decreased kidney or liver function.

They may also be necessary for those with disorders that affect protein metabolism, such as homocystinuria and phenylketonuria.

However, going on a low-protein diet requires careful planning to prevent health issues and nutritional deficiencies.

Additionally, there are other risks and potential drawbacks you should consider before beginning a low-protein diet.

Summary A low-protein diet generally reduces protein intake to make up around 4–8% of your daily calories. It may be beneficial for those with certain health conditions, but there are also some risks to consider.

Health Benefits of a Low-Protein Diet

The benefits of a low-protein diet mostly apply to people with specific health conditions or diseases, rather than those who are generally healthy.

Excess protein is typically broken down by the liver, producing a waste product called urea, which is excreted by the kidneys (2).

Decreasing protein intake can ease the workload of the liver and kidneys, which can be beneficial for people with liver disease or impaired kidney function.

This helps improve protein metabolism and prevents a buildup of urea in the bloodstream.

Having high levels of urea in the blood causes symptoms like fatigue, loss of appetite, weight loss and changes in mental status (3).

It may also be associated with a higher risk of type 2 diabetes and death in those with heart failure (4, 5, 6).

Reducing protein intake is also necessary for those with genetic disorders that affect protein metabolism, such as homocystinuria and phenylketonuria.

These disorders impair the breakdown of specific amino acids, so reducing protein intake can help minimize symptoms (7, 8).

Some research has also found that low-protein diets may be associated with several health benefits for the general population.

According to one review, restricted protein intake in middle-aged adults was associated with increased life expectancy and reduced risks of chronic conditions like cancer, heart disease and diabetes (9).

However, more studies are still needed to evaluate the potential long-term benefits of protein restriction in healthy adults.

Summary Reducing protein intake can be beneficial for those with conditions like liver and kidney disease, phenylketonuria and homocystinuria. One review also reported that it may increase longevity and reduce the risk of chronic disease.

Potential Side Effects

Protein is an essential nutrient crucial to growth and development.

Your body uses it to form the foundation of your muscles, skin and bones, produce important enzymes and hormones, and build and repair tissues (10).

Studies show that a protein deficiency can have detrimental effects on health, including impaired immune function, muscle loss and decreased growth in children (11, 12, 13).

Other possible symptoms of a protein deficiency include swelling, anemia, fatty liver disease, hair loss and reduced bone density (10, 14, 15).

Besides the possible health risks involved, decreasing your protein intake can be very challenging.

Not only does following a low-protein diet take a bit of creativity, it also requires careful planning to ensure you meet your other nutritional needs.

This is because high-protein foods supply a good number of calories and key micronutrients.

For example, beef is rich in B vitamins, iron and zinc, while beans are a good source of magnesium, phosphorus and potassium (16, 17).

When following a low-protein diet, it’s important to ensure you’re getting these nutrients from other sources to prevent nutrient deficiencies.

However, because of its potential dangers and health risks, a low-protein diet is not advisable unless you have an underlying health condition and are under direct medical supervision.

Summary Protein deficiency can cause impaired immune function, muscle loss and decreased growth. It can also be challenging to reduce protein intake and requires careful planning to meet your nutritional needs.

Foods to Eat

In most diets, meals tend to center around high-protein foods like meat or plant-based proteins.

However, on a low-protein diet, your meals should be focused on the low-protein components of meals, such as grains, vegetables or fruits.

You can still include meat and plant-based proteins in your diet, but you should use them as side dishes and consume them only in small amounts.

You may also need to bump up your intake of healthy fats, which can provide extra calories to help you meet your daily needs.

Healthy Low-Protein Foods to Include

• Fruits: Apples, bananas, pears, peaches, berries, grapefruit, etc.
• Vegetables: Tomatoes, asparagus, peppers, broccoli, leafy greens, etc.
• Grains: Rice, oats, bread, pasta, barley, etc.
• Healthy fats: Includes avocados, olive oil and coconut oil

Summary On a low-protein diet, you should consume plenty of fruits, vegetables, grains and healthy fats and minimal amounts of high-protein foods.

Foods to Avoid

Protein is still a necessary part of the diet, even if you’re on a low-protein diet. So don’t avoid it altogether.

However, if you’re on a low-protein diet, you should consume high-protein foods like animal products and plant-based proteins in moderation.

To do this, up your intake of healthy, low-protein foods like fruits and vegetables. At the same time, you may need to scale back on your protein serving sizes.

For example, a serving of chicken is generally about 4 ounces (113 grams).

However, on a low-protein diet, you may need to cut that amount in half and stick to a 2-ounce (57-gram) serving to keep your protein intake in check.

High-Protein Foods to Limit or Avoid

• Meats like chicken, turkey, beef and pork
• Fish and shellfish
• Eggs
• Legumes, including beans, peas and lentils
• Dairy products like milk, cheese and yogurt
• Soy products like tofu, tempeh and natto
• Nuts like walnuts, almonds and pistachios
• Seeds like chia seeds, flaxseeds and hemp seeds

Summary If you’re on a low-protein diet, limit high-protein foods like meat, fish, eggs, legumes, dairy products, soy, nuts and seeds. At the same time, increase your intake of healthy low-protein foods like fruits and vegetables.

3-Day Sample Menu

Here’s a three-day sample menu to get you started.

Day 1

• Breakfast: 1 boiled egg with 2 cinnamon pancakes.
• Snack: 1 medium apple with 1 tbsp (16 grams) peanut butter.
• Lunch: 1 cup (140 grams) cooked spaghetti with vegetable Bolognese and 1/2 cup (67 grams) roasted asparagus.
• Snack: 1 cup (76 grams) strawberries with 1 ounce (28 grams) dark chocolate.
• Dinner: Tortilla wrap with 1 ounce (28 grams) canned tuna and 1/2 avocado. Garnish with tomatoes, lettuce and onions.
• Snack: 1 cup (148 grams) frozen blueberries.

Day 2

• Breakfast: 1 cup (28 grams) cereal with 1/2 cup (119 ml) almond milk and 1 large orange.
• Snack: 1 medium banana.
• Lunch: Sandwich with 1 ounce (28 grams) deli meat and 1/2 cup (55 grams) green beans. Garnish with lettuce, tomatoes and mayonnaise.
• Snack: 5 crackers with 1 ounce (28 grams) cheddar cheese.
• Dinner: 2 ounces (57 grams) grilled chicken with 1/2 cup (90 grams) cooked white rice and 1/2 cup (78 grams) steamed broccoli.
• Snack: 1 cup (245 grams) coconut yogurt with 1/2 cup (72 grams) blackberries.

Day 3

• Breakfast: 2 slices toast with 1 ounce (28 grams) cream cheese and 1 medium apple.
• Snack: 1 cup (151 grams) frozen grapes.
• Lunch: Cauliflower burger and 1 small baked sweet potato topped with 1 tablespoon (14 grams) olive oil.
• Snack: 1/2 cup (70 grams) baby carrots with 2 tablespoons (30 grams) guacamole.
• Dinner: Greek salad with 2 cups (60 grams) spinach and 1 ounce (28 grams) feta cheese. Add cucumbers, tomatoes, olives and onions to taste, top with 1 tbsp (14 grams) olive oil. Serve with 1 slice pita bread.
• Snack: 3 cups air-popped popcorn.

Should You Try a Low-Protein Diet?

If you are living with a condition that affects your liver or kidneys or interferes with protein metabolism, a low-protein diet may be necessary to help reduce your symptoms.

However, for healthy individuals, there’s limited evidence that it has any health benefits.

Also, a low-protein diet requires careful planning to minimize potential health risks and nutritional deficiencies. It should only be done under medical supervision.

It’s crucial to consult a doctor or dietitian before starting a low-protein diet. Not only can they help determine if it’s a good option for you, but they can also provide guidance to ensure your diet is still healthy and well-rounded.