The Potential Side Effects of a High Protein Diet

Parul Dube

January 31, 2023

Everyone is familiar with high-protein diets, especially the Atkins and zone diets, which have recently gained popularity, though they have been prevalent since the 1990s. Other diets like the caveman and paleo diets can vary in macronutrient ratios, but they are typically high in protein. While the standard diet chart for keto focuses on fat, it can also be relatively high in protein content. Protein is a significant macronutrient of a balanced healthy diet as it aids in building and repairing muscles, organs, and bones. 

It is always essential to follow what the nutritional experts say and not exceed the daily consumption range. When calculating the total amount of protein in your diet, consider how much protein you eat or should eat from your food and drink sources. It is also crucial to analyse the supplement intake, like protein powder. Also, one should be aware of the high-protein diet’s side effects.

The Adequate Protein Consumption

The amount of protein consumed by men and women averages from 50-55 grams per day for women to 60-70 grams for men. For ordinary people (with little physical activity), the daily protein intake recommendation is 0.8-1.0 grams per kg of body weight. When you eat more than this, you’re on a high-protein diet. However, remember that not everyone requires the same amount of protein. For example, for Elite athletes, protein consumption can be 3.5 grams as per kg of their body weight without experiencing any adverse effects. And in the long run, most healthy adults can tolerate 1.2 – 1.5 g of protein per kg of body weight per day.

All protein sources have a biological value number. However, as per the nutrient profiles, animal protein ranks higher than plant protein. Therefore, if you want to meet your daily protein requirement solely through a plant-based diet, you’ll need to eat a lot more plants (nearly double) to match the protein from a smaller portion of animal-based food.

The HealthifyMe Note

High protein diets can help in reducing fat and promote weight loss. In addition, they leave you feeling fuller for longer and support muscle retention. But where there are pros, there are also cons. Thus, one must be aware of these high-protein diets’ risks.

Best Sources of Protein

When you choose what to eat among a variety of high-protein dishes, it is in your hands to choose the healthier options. It will enable you to reduce the negative impacts of a high-protein diet. There are various healthy protein sources, which include: 

  • Grass-fed lean meats & poultry (pasture-raised)
  • Wild Fish
  • Pastured hens producing eggs
  • Organic dairy
  • Legumes
  • Nuts
  • Whole grains

High Protein Diet Side Effects or Risks

Consuming an excess of anything can always be problematic to your health and life. The same is in the case for high proteins. As per research, overconsumption can lead to dangerous side effects and harm the body. On the other hand, there are potential health benefits for a particular group of people. Still, for many people, excessively high amounts of protein for prolonged periods will not go down well with your system. The various risks include:

Weight Gain

The weight loss process via high-protein diets is only for a brief period. The body stores the excessive proteins as fat while the different amino acids excrete. However, it ultimately leads to weight gain in the future if you consume too many calories under the pretext of enhancing your protein intake. 

As per a study in 2016, when proteins replaced carbohydrates, it led to weight gain. However, when proteins replaced fats, there was no significant weight gain.

Bad Breath

Bad breath is another problem associated with consuming too many proteins. It is due to a metabolic state of the body called ketosis, where they release chemicals with an unpleasant smell. Even flossing or brushing won’t solve your problem. You have to switch to healthy habits and probably chew gum to eradicate some of the odour. 


Consuming too much protein causes the kidneys to work twice as hard to flush it out through urine, which makes you thirsty. As a result, you lose essential minerals such as magnesium, potassium, and sodium. Therefore, even if you consume more protein, you must also ensure that you consume various fruits and vegetables with high moisture and mineral content.

Bowel Problems

High protein diets can easily wipe out healthy gut flora because they lack pre-biotics, a fibre that helps fuel beneficial bacteria. It can cause a wide range of bowel issues, the most prevalent of which are constipation and diarrhoea. Stomach cramping and bloating are common. The problem with high-protein diets that exclude carbohydrates is that they are low in fibre. Keep track of your bowel movements and stay hydrated while eating fibre-rich diets. It is essential for dealing with constipation. Multiple studies have declared that a high protein diet causes bowel problems. However, the exact aetiology of bowel problems associated with higher protein is not yet fully understood. 

May Cause a Nutritional Deficit

A diet may be protein-rich but still lack essential micronutrients. Of course, your platter should always get balanced to meet your body’s nutritional requirements. However, in cases where the body receives excess proteins, it can lead to a metabolic strain on the liver, kidney, and bones. In addition, it may lead to leaching out of nutrients from these organs, reducing the overall biological nutrient balance. 

May Lead to Cardiovascular Problem

A few high-protein diets comprise a higher intake of red meats and fattier proteins. But not all proteins behave in the body in the same manner. 

According to research, plant protein leads to a lower mortality risk than animal proteins. It suggested that plant proteins result in longevity, and daily consumption of around 3% of plant proteins could diminish the risk of death by about 5%. 

The Benefits of a High Protein Diet

Most people turn towards a high-protein diet to lose weight as it helps curb hunger or build muscles. But, as per a study, it has other benefits as well. 

Fat Mass Reduction & Improvement in Lean Muscles

As per literature reviewed in the American Journal of Clinical Nutrition, multiple analyses of short-term and controlled feeding studies, high-protein diets focus on enhancing weight loss, fat mass loss, plus a drop-in waist circumference for participants. In addition, the final reports have also shown that you can preserve lean mass due to these high protein diets. However, make sure to consult a nutritionist before you start implementing considerable amount of protein in your diet.

Lowers Triglyceride Levels

A high protein diet will benefit people with type 2 diabetes because it lowers triglycerides and fat lipids in the blood. Whereas in the case of a low protein diet, you can be prone to the risk of cardiovascular diseases. 

Repair Tissues

Proteins play a significant role in repairing tissues; hence, protein diets are great recommendations for healing wounds & injuries. That is because the body seeks proteins as a nutritional aid for wound healing, thus enhancing the requirement of proteins and calories in the injured area.

Are High Protein Diets Suitable for All?

We all know that high protein diets are safe for healthy individuals and have no health implications. But we should also be aware that these diets are not for everyone. 

You should follow a high-protein diet under the strict guidance of a medical consultant or professional. However, you should not overload your body with excessive proteins and lead your body to harmful implications or unwanted health issues. 

Some protein choices you make for your body may not be healthy as they contain saturated fats, which can raise cholesterol levels. In addition, it can be bothersome for your kidneys when you consume too much protein. The pattern is such that there will always be negative consequences for patients with a hiked cholesterol count or any renal dysfunction. Therefore, to counterbalance this function, you must increase your water intake and not run the risk of dehydration. 

You must determine if a diet is suitable or not for you first. Then, your doctor can guide you through the various pros and cons of the process as per your individual needs and requirements. But the most important thing is to eat a healthy, balanced diet and keep yourself engaged in an active lifestyle. 

Recognise and align your life goals and plans with your needs. For example, do you want to gain muscle or lose weight? Do what is best for your health; your body can sustain it for longer.

Are High Protein Diets Good for Weight Loss? What Do the Experts Say?

When healthy people follow a high-protein diet for a short period, it is not harmful and will result in effective weight loss and leave you feeling satiated. But restricting carbs in a high-protein diet for a longer time could result in severe health issues. 

Studies to prove the same is still in motion. Very few carbohydrates in your diet lead to nutritional deficiencies due to insufficient fibre. You could suffer from headaches and constipation, along with the bad breath. Diets comprising red meat or full-dairy products can take you closer to heart diseases. High protein diets make the kidney function worse as it becomes a pain to eliminate the waste products of protein metabolism. Smartly choose your proteins by including nuts, fish, beans, lean beef, pork, etc. You can also consume low-fat dairy products. 

The quality of your carbs is also crucial. So, choose nutrient-dense and high fibre-complex carbohydrates and chuck the processed carbs out of your diet. Always vouch for fresh fruits, vegetables, and whole grains. Before starting a weight-loss diet, keep your health conditions a priority, especially if you have diabetes or kidney disease. Weight loss may be temporary if you cannot change your eating habits. Only start a plan if you can stick to a method for as long as you get the best results. 


You should take a lot of factors into consideration while planning your daily protein count. These factors involve age, gender, activity, health, diet, and other variables. In the case of adults, though, we consider the total body weight. It decides your daily protein intake. For example, adults who shy away from physical activity should ideally consume 0.8 grams of protein per kilogram of their body weight. 

If you are a weight-lifter or exercise frequently with body weights, you can freely consume up to 1.2 – 1.7 grams of protein per kg. Elite athletes are privileged to consume around 3.5 g of protein per kilogram of their body weight. Experts say that healthy adults can consume 2 grams of protein per kilogram of body weight in the long run. 

Frequently Asked Questions (FAQs)

Q. Can a high protein diet be harmful?

A. A high-protein diet is not harmful to healthy people who follow it for a short period. However, an excess amount of proteins not prescribed by a nutritionist can be detrimental to the body. In addition, a balanced diet is always beneficial.

Q. Are there any side effects to a high protein diet?

A. High protein diet, when consumed for long periods, can lead to calcium homeostasis and bone disorders, renal function disorder, enhanced cancer risk, liver function disorder, and enhanced coronary artery disease. 

Q. What happens when you start eating more protein?

A. Consuming more proteins will store them in your body as fats, leading to weight gain over time. However, it can also lead to bad breath, constipation, dehydration, and diarrhoea. 

Q. What organ is affected by too much protein?

A. Overeating protein can cause harm to your liver. When the liver gets overloaded, ammonia and other toxic substances enter the bloodstream. In addition, too much protein intake can worsen the symptoms in people with preexisting kidney disease or trigger kidney damage in healthy individuals. 

Q. What is the kidney problem that too much protein can cause?

A. When too much protein is in your urine, the glomeruli stop working correctly, and excessive proteins enter the urinary system. This damaged condition of glomeruli is nephritis. 

Q. What is protein poisoning?

A. Protein poisoning is when the body consumes excessive proteins without too many fats and carbohydrates for long periods. It can have noticeably harmful effects on renal filtration and electrolyte balance. Overall, you must eat a healthy, balanced protein amount. 

Q. What are the pros and cons of a high protein diet?

A. Some pros of such a diet include better regulation of appetite, muscle & strength gain, and improved metabolism, while some cons include weight gain and imbalanced nutrition. When choosing high-protein foods, be sure to consume them in moderation. 

Q. Is 200g of protein too much?

A. Yes, 200 grams of protein is too much and can be unhealthy for a large population of adults. An ideal amount is always a daily average of 0.8 grams of protein per kilogram (kg) of body weight. However, elite athletes can consume 3.5 g per kg of body weight without side effects.

Q. How much protein is safe per day?

A. 100 grams of protein per day is a safe bet for consumption. The general requirement suggested is 0.8 grams of protein per kg of body mass. Consume according to your age, gender, weight, and health.  

Q. Can too much protein make you tired?

A. Yes, overconsumption of proteins can tire you because of the pressure applied to the liver, kidneys, and bones. In addition, an amino acid called tryptophan produces serotonin which makes your body sleepy and you experience fatigue.

About the Author

Parul holds a Masters of Medical Science in Public Health Nutrition from the University of Glasgow, Scotland, and has worked across the globe from the U.K to New Zealand (NZ) gaining her License with the Health Professionals Council (HPC, UK) and the NZ Nutrition Council. From being a Gold medalist in Clinical Nutrition to being awarded an internship with World Health Organisation (WHO, Cairo, Egypt) and Contracts with CDC Parul has had a wide spectrum of work experiences. She is very passionate about Nutrition and Fitness and holds strong to her guiding mantras ‘ Move more’ and ‘Eat Food that your grandmother can recognize’!

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