Published On By Rachel Nall

Risk And Side Effects Of High Protein Diet

Looking to be healthier, many people choose high-protein diets because they can help with losing weight, building muscle, and keeping you full.

However, these diets also have risks and side effects that you should understand before deciding if they’re right for you.

Focusing too much on protein could mean missing out on other important nutrients or experiencing side effects.

If you’re thinking about trying a high-protein diet, this article will explain the potential side effects and things to watch out for.

Side Effects Of High Protein Diet

  1. Bad Breath

    A high-protein diet may cause bad breath or halitosis through several mechanisms. When the body metabolizes protein, it produces ammonia as a byproduct, which has a strong odor and can contribute to foul-smelling breath. Very high protein diets that induce ketosis by burning fat for energy instead of glucose can result in the production of ketones like acetone. These ketones can be released in the breath, causing a distinct fruity or acetone-like odor. High protein diets also increase the body’s water needs due to the kidneys processing protein byproducts. Digestive issues such as constipation from high protein intake can lead to the buildup of gases in the digestive system, which may be released through the mouth, contributing to bad breath.

  2. Weight Gain

    When the body receives more protein than it needs for muscle repair and growth, the excess protein is typically stored as fat.

    If calorie intake exceeds energy expenditure, the surplus calories from protein might be attributed to weight gain.

    Consuming protein-rich foods, which can be high in calories, can result in an excess calorie intake if not balanced with physical activity.

    The body could convert excess protein into glucose through gluconeogenesis, and this glucose can be stored as fat if not used for energy.

    Many protein-rich foods, such as meats and dairy products, are also high in fat, which could further increase calorie intake and contribute to weight gain.

    Research from a 2016 study highlighted a significant link between weight gain and diets where protein replaced carbohydrates. This suggests that the source of calories matters in the context of weight management when increasing protein intake. It is crucial to maintain a balance between protein, carbohydrates, and fats to avoid unintentional weight gain.

  3. Heart Disease

    Many protein-rich animal products, such as red meat and full-fat dairy, are high in saturated fats and cholesterol, which can raise LDL (bad) cholesterol levels and might cause plaque buildup in the arteries, elevating the risk of heart disease.

    Diets high in certain proteins, especially from processed meats, may cause inflammation in the body, a risk factor for heart disease, as it could damage blood vessels and contribute to arterial plaque buildup.

    High protein intake could also strain the kidneys, particularly in people with preexisting kidney conditions, potentially leading to hypertension, an important risk factor for heart disease.

  4. Diarrhea

    Consuming large amounts of protein-rich foods, especially those high in fat like red meat, can be difficult for the digestive system to process optimally, leading to gastrointestinal distress and diarrhea.

    Excessive use of protein supplements, which often contain artificial sweeteners and sugar alcohols like sorbitol or maltitol, can also have a laxative effect.

    A high-protein diet low in fiber can disrupt the bacterial balance in your gut, causing excess digestive issues. Fiber is important for managing a healthy gut microbiome, and a lack of it can cause digestive disturbances.

    High protein diets could also increase the need for water, as the kidneys require more water to process and eliminate protein byproducts.

  5. Affect Mental Health

    Excessive focus on protein might lead to a lack of essential nutrients like carbohydrates, vitamins, and minerals.

    Carbohydrates are crucial for brain function as they provide glucose, the brain’s primary energy source. A deficiency in carbohydrates can result in low energy levels, poor concentration, and mood swings.

    A high protein diet low in fiber can negatively impact gut health, which is closely linked to mental health. A disruption in the gut bacteria might contribute to anxiety and depression.

    High protein diets also increase the need for water, as the kidneys work harder to eliminate protein byproducts, and dehydration can affect cognitive function and mood, causing fatigue, confusion, and irritability.

  6. Constipation

    Constipation is a common issue related to high-protein diets that limit carbohydrate intake, as stated by 44 percent of participants in a recent study. This is largely due to the fact that these diets often lack sufficient fiber, an integral component for maintaining regular bowel movements and promoting healthy digestion.

  7. Kidney Health

    Excess nitrogen from amino acids in proteins can stress the kidneys, especially in individuals with preexisting kidney conditions. Damaged kidneys may struggle to eliminate the additional waste products generated by the metabolism of excess protein.

    Consuming a high-protein diet increases the production of urea and ammonia, which can strain the kidneys over time and potentially lead to kidney damage or worsen existing kidney conditions.

    However, a 2012 study comparing low-carbohydrate, high-protein diets with low-fat diets in healthy obese adults found that over two years, the high-protein diet did not show significantly harmful effects on renal function compared to the low-fat diet.

    The study observed no noticeable detrimental impacts on renal filtration, albuminuria, fluid, or electrolyte balance with the high-protein diet.

  8. Loss Of Bone Health

    Consuming protein from animal sources might increase acidity in the blood. It can disrupt hormonal balance, affecting hormones like insulin-like growth factor 1 (IGF-1) and parathyroid hormone (PTH) involved in bone metabolism. Imbalances in these hormones can interfere with bone remodeling processes, potentially leading to bone loss.

    Protein metabolism also generates acidic byproducts like sulfuric acid, requiring the body to maintain a balanced pH level. Excessive protein intake can strain the kidneys, which regulate acid-base balance, and over time, this can further impact bone health as calcium is mobilized to buffer acidity.

  9. Brain Fog

    A high protein diet can lead to brain fog, characterized by confusion, forgetfulness, and difficulty concentrating. Such diets may prioritize protein intake over essential nutrients like carbohydrates, which provide the glucose necessary for optimal brain function. Insufficient carbohydrates can lead to low blood sugar levels, contributing to brain fog symptoms. Focusing excessively on protein may lead to deficiencies in micronutrients crucial for brain health, such as B vitamins, vitamin D, and omega-3 fatty acids. These nutrients support neurotransmitter function and cognitive performance.

  10. Dehydration

    Dehydration can be a concern when consuming high amounts of protein, as the body expels excess nitrogen through fluids, potentially leading to reduced hydration levels. Research has shown varying results regarding the impact of protein intake on hydration levels. While a small 2002 study on athletes suggested that higher protein intake correlated with decreased hydration, a 2006 study concluded that the effect on hydration was minimal.

  11. Increase Cancer Risk

    Diets high in animal proteins can promote inflammation in the body, a known factor in cancer development, by damaging cells and tissues and potentially initiating cancerous growth.

    Cooking meats at high temperatures can produce carcinogenic compounds like heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), which are linked to cancers such as colorectal, pancreatic, and prostate cancers.

    High protein diets can alter gut microbiota composition, potentially increasing inflammation and the risk of gastrointestinal cancers.

    Specifically, red and processed meats have been classified as carcinogenic to humans based on results linking their consumption to cancer risk.

Benefits of a High Protein Diet

A diet rich in protein can lower triglyceride levels, which could be suitable for people with type 2 diabetes. A high-protein diet may help reduce fats in the blood, which helps keep your heart healthy and improves how diabetes is managed.

It may help with losing weight, makes insulin work better in your body, and raises HDL cholesterol, which is good for your heart and helps lower triglycerides.

Eating more protein may help build and repair muscles, especially when you do exercises that make your muscles stronger. This can increase your muscle mass, but the results vary based on how many calories you eat, how you exercise, and where your protein comes from.

Proteins are also important for fixing tissues in your body, like healing cuts and injuries. They help make collagen and boost your immune system, which helps you heal faster and reduces the chance of problems during healing.

If you’re thinking about eating more protein, it’s a good idea to talk with a nutritionist or doctor first. They can help you decide how much protein is right for you based on your health and fitness goals.

Also See:

High Sources Of Protein

  • Beef
  • Poultry
  • Pork
  • Beans
  • Lentils
  • Chickpeas
  • Almonds
  • Chia seeds
  • Flaxseeds

How Much Protein Do You Need Everyday?

For most adults with minimal physical activity, the recommended daily average is 0.8 grams of protein per kilogram (kg) of body weight.

If engaging in regular weight or resistance training, consuming up to 1.2 to 1.7 grams per kg of body weight daily may be beneficial.

Elite athletes, however, may require higher amounts, with some consuming up to 3.5 grams per kg without side effects.

The Dietary Guidelines for Americans often recommends that adults should derive between 10% and 35% of their daily energy intake from protein.

Who should avoid eating high protein?

Some people need to be careful with high-protein diets because of certain health conditions or risks that could cause problems:

  • Kidney and Liver Problems: If you have experienced kidney or liver problems already, it’s important to limit how much high-protein food you eat. Too much protein can strain these organs and lead to more health issues.
  • Low Carbohydrate Diets: Diets that are low in carbs often have a lot of protein instead. It’s important to balance this properly because too much protein can be a problem. People on low-carb diets should keep an eye on how much protein they’re getting.
  • Gout and Nutrient Deficiencies:If you have gout or don’t get enough essential nutrients that help your body process protein (like glucose, arginine, glutamine, and vitamins B-6, B-12, and folate), you should be cautious with high-protein diets. These diets might make these conditions worse if you don’t manage them carefully.

When to see your doctor?

Before you start a high-protein diet, it’s important to talk to a doctor to see if it’s right for you and your health goals.

Here are some things to keep in mind:

  • Existing Health Issues: If you have kidney problems, liver issues, or other health conditions, it’s best to check with your doctor first. A high-protein diet might affect these conditions, so it’s important to get advice from the doctor.
  • Unexpected Side Effects: If you notice unusual problems like ongoing stomach issues, strange changes in your weight, or ups and downs in your energy levels while on a high-protein diet, it’s wise to see a doctor.

If you’re thinking about sticking to a high-protein diet for a while, talk to your doctor about it. They can help you figure out how to eat well, make sure you’re getting all the nutrients you need, and watch out for any long-term effects on your health.

Frequently Asked Questions

  1. Can Excessive Protein Intake Lead to Nutrient Deficiencies?
    Consuming high amounts of protein might displace other essential nutrients, impacting overall dietary balance. It is vital to maintain a varied diet to prevent deficiencies.
  2. Can a high-protein diet affect hormonal balance?
    Excessive protein intake, especially from animal sources, can disrupt hormonal balance, potentially affecting reproductive hormones and thyroid function. Opting for plant-based proteins and maintaining a varied diet can help maintain hormonal health.
  3. Who Should Avoid Consuming High Amounts of Protein?
    People with kidney or liver conditions, digestive disorders, and those at risk of nutrient deficiencies should avoid consuming high amounts of protein.
  4. Should athletes and active people follow a high-protein diet indefinitely?
    While protein is crucial for optimal muscle repair and growth, athletes and active people should periodically assess their protein needs and adjust their diets accordingly to prevent potential health risks associated with prolonged high protein intake.


Protein is very important for our bodies because it may help with muscle development, fixing tissues, and making hormones and enzymes. However, relying too much on these diets can cause problems.

Sometimes, high-protein diets can lead to side effects such as headaches, stomach issues like diarrhea, and even serious health problems like higher chances of heart disease, issues with brain function, and kidney problems.

To get the most out of protein’s benefits while avoiding problems, it’s best to eat a variety of foods that give the body all the nutrients it needs. This balanced way of eating not only keeps you healthy but also help you develop good eating habits that last a long time.

  • This article is for informational purposes only and should not be considered medical advice or a replacement for medical advice.
  • It is not recommended to disregard/delay seeking professional medical advice or treatment because of what you read or accessed through this article.
  • The results may vary from individual to individual.
  • It is recommended to consult your doctor for any underlying medical conditions or if you are on any prescribed medicines before trying any tips.

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