Why Too Much Protein Could Be Harming Your Health and the Planet

Protein plays a vital role in keeping the body healthy, supporting everything from muscles and bones to skin and organs. It also helps with wound healing, tissue repair, and provides lasting energy. Yet while many recognise its benefits, experts warn that too much can cause unexpected health and environmental issues.

Over the past two decades, protein consumption in the US has slowly climbed. Daily intake rose from around 90–95 grams per person in 2000 to 100–110 grams by 2020, according to USDA and NHANES data. Trends like high-protein diets, increased meat consumption, and fitness culture have likely driven this shift.

For the average healthy adult, about 0.8 grams of protein per kilogram of body weight is enough to maintain muscle and overall function. Those who are very active may need slightly more—up to 1.2 grams per kilogram—without overdoing it. Anything beyond 2 grams per kilogram is considered excessive and can lead to problems.

Eating too much protein doesn't just go to waste—it can harm the body. Side effects include dehydration, bad breath, headaches, and digestive troubles like stomach pain or diarrhoea. Over time, it may even strain the kidneys. The excess is also excreted as nitrogen-rich urea, which enters wastewater and can disrupt aquatic ecosystems by introducing high nitrogen levels.

To meet protein needs without overloading, experts suggest a balanced approach. Mixing plant-based and animal-based proteins helps, as does choosing leaner animal sources. They also advise caution with protein supplements, which can push intake beyond necessary levels.

Protein remains essential for health, but moderation is key. Most people need between 0.8 and 1.2 grams per kilogram of body weight, depending on activity levels. Beyond that, the risks—both to personal health and the environment—begin to outweigh the benefits.