How much protein is too much?

How Much Protein is too much?

Proteins are the most versatile molecules for the human body and are a key factor to almost all biological processes. The average recommended dietary allowance for protein is calculated using the ratio of 1 gram of protein for every 1 kilogram of a person's body weight.

The recommended dietary allowance or RDA for protein depends on factors, such as:

•          Age

•          Gender

•          Pregnancy and breastfeeding

•          Activity levels

Adults are generally recommended to eat 0.8 g per kilograms (kg) of body weight daily.

Recommended protein intake

According to the Institute for Medicine (IOM), the daily RDA for protein is as follows:

 Life stage and gender                           RDA in grams (g) per day

Infants and children 

0–6 months                                                     9.1

6–12 months                                                   11.0

1–3 years                                                        13.0

4–8 years                                                        19.0


9–13 years                                                      34.0

14–18 years                                                    52.0

19–70 years and older                                    56.0


9–13 years                                                      34.0

14–70 years and older                                    46.0

Pregnant or breastfeeding women 

All ages                                                            71.0


Being physically active can increase the RDA of protein that people should eat.

A 2016 study recommends eating:

•          1.0 g of protein per kg of body weight with minimal activity levels

•          1.3 g of protein per kg of body weight with moderate activity levels

•          1.6 g of protein per kg of body weight with intense activity levels


Anyone who is pregnant or breastfeeding will need to eat a lot more protein than other people.

Some studies have also found that people may need to increase the protein intake as they age.

Side effects of too much protein

Consuming too much protein on a regular basis can cause intestinal discomfort and indigestion.

People can typically consume 2 g of protein per kg of their body weight daily, long-term, without any significant side effects.

Some people, such as elite athletes, may be able to eat as much as 3.5 g per kg of body weight daily without any side effects.  However for most of us eating too much protein for a long time can cause health problems.

Such as:

•          Intestinal discomfort and indigestion

•          Dehydration

•          Unexplained exhaustion

•          Nausea

•          Irritability

•          Headache

•          Diarrhoea

There are serious risks associated with chronic protein over consumption, including:

•          Cardiovascular disease

•          Blood vessel disorders

•          Liver and kidney injuries

•          Seizures

•          Death

Doctors have also linked certain conditions to chronic protein over consumption:

•          Type 2 diabetes

•          Cancer

•          Osteoporosis


Are high protein diets safe?

The IOM (institute of occupational medicine) recommend people get between 10 and 35 percent of their daily energy intake from protein.

Some people may need more protein than others,

Such as:

•          Athletes

•          Pregnant and breastfeeding women

•          People who do physically demanding jobs


Researchers are still unsure whether very high protein diets are safe, especially when someone is also cutting back on their carbohydrate intake.

What is the effect on weight loss?

It is likely that high-protein diets promote weight loss because high protein foods tend to promote a feeling of fullness, helping reduce hunger cravings and overeating.

More research is needed to understand the relationship between high protein diets and weight loss however.

How can you healthily eat high-protein diets?

A large variety of plant and animal-based foods are high in protein, including:

•          Meats

•          Dairy products

•          Nuts

•          Legumes

•          Seeds

•          Unrefined wholegrain cereal and wheat products

Not all protein-rich foods are ideal for people looking to lose weight or maintain a healthy diet. 

Examples of protein-rich, low-calorie foods include:

•          Skinless chicken breast fillet (less than 26 g protein and 113 calories)

•          6 oz Greek yogurt (less than 17 g protein and 100 calories)

•          2 large eggs (less than 12 g protein and 144 calories)

•          ½ cup tofu (less than 10 g protein and 95 calories)

•          2 tablespoons (tbsp) peanut butter (less than 8 g protein and 190 calories)

•          1 oz almonds (less than 6 g protein and 165 calories)

•          1 cup cooked oatmeal (less than 6 g protein and 165 calories)

•          ½ cup cooked quinoa (less than 4 g protein and 110 calories) 

Who should avoid eating too much protein?

Side effects from protein over consumption may contribute to kidney and liver conditions.

Some people cannot eat as much protein as others because of conditions that interfere with digestion and people with the following conditions should avoid over eating protein

•          Kidney and liver conditions

•          Low carbohydrate intake

•          Starvation

•          Gout

•          being deficient in nutrients needed for protein metabolites, such as glucose, glutamine, and vitamins B-6, B-12, and folate.

Claire Edwards