From kidney strain to fatigue, here are 5 expert-backed signs you’re eating too much protein, plus how to balance your diet for better health.
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Turns out you can have too much of a good thing
Aydan Metev//Getty Images
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Why does your body need protein?
How much protein should we be eating?
Are women in their 20s and 30s generally low in protein?
What are the best protein-rich foods?
And is eating too much protein bad for your health?
Signs you could be eating too much protein
Scan the aisles at your local supermarket and you're guaranteed to spot a product that's labelled 'high-protein' — be it cheese, chocolate, yoghurt or chicken skewers. High-protein supermarket foods feel like 2025's answer to 'low-carb' or 'sugar-free'.
Reema Pillai, a sports dietitian, thinks social media, clever marketing, and the renewed interest in sustainable weight loss have pushed protein into the spotlight, making eating increasing amounts a major trend.
"Many 'high-protein' products are clever marketing," she explains. "For example, 'high-protein' yoghurt pots, often contain the same amount of protein as a good quality plain Greek yoghurt, which is half the price."
And it's not just your bank balance that can be impacted by eating too much protein — whether that's through these supermarket foods or your diet generally.
"If you have existing kidney conditions, excess protein can be dangerous as it causes elevated creatinine levels, or blood urine nitrogen levels on blood tests," Pillai says. "High protein diets don't cause kidney issues but, for those with existing issues, high protein intake is not generally advised."
VJ Hamilton, a BANT-registered nutritionist and functional medicine practitioner, has also spotted the side effects of overdoing protein. "I’ve worked with many clients, particularly those doing high-intensity training or following low-carb, high-protein diets, where their protein intake has been too excessive for what their body can actually process," she says.
Here, Pillai and Hamilton break down everything you need to know about protein — including the signs you could be eating too much.
"Protein is a major component of building muscles, bone, skin and hair, and is vital for growth and repair," Pillai tells Cosmopolitan.
"Proteins are required to create antibodies, which are crucial to fight off infections. It's also used to support the creation of enzymes and hormones, as well as being important to build muscle, especially as we exercise and grow older."
It makes sense then that lots of us are trying to eat more for good health. But, how much protein should we be eating? Well, according to Pillai, that depends on a few different things.
"The average woman in their 20s and 30s should aim to consume around 1-1.2g of protein per kilogram (kg) of body weight," she explains. "For example, a woman weighing 70kg would require around 70g of protein.
"However, protein requirements for a physically active woman can be as high as 1.6-2g per kg of body weight, especially if they are regularly strength training. Women who are pregnant and breastfeeding may also have higher than standard protein requirements, but more protein isn't always required for everyone, so it is important to seek professional advice when looking to understand your protein needs."
Stress and perimenopause (the years before menopause or your final period, usually in your forties or fifties) can also impact your protein needs, Hamilton adds.
"In clinic, I regularly see women who are feeling tired, struggling with hair loss, poor recovery, or low mood and their diet, while technically adequate, is often light on protein and heavier on quick carbs or snack-style meals," Hamilton explains. "Even subtle protein insufficiency can impact your ability to make neurotransmitters, stabilise blood sugar and repair tissue."
You'd be forgiven for thinking so, as lots of these high-protein supermarket foods seem to be marketed at women. However, the truth is more nuanced.
"Some women can easily meet their protein requirements through their regular meal patterns, especially if they consume animal protein at each meal of the day," Pillai explains.
"However, women in their twenties and thirties may struggle meeting protein requirements due to several factors, such as busy lifestyles or disordered relationships with food, which may possibly lead to skipping meals or having restrictive eating patterns. Relying on convenience and ease can also lead to lower protein intakes."
Hamilton adds: "A simple rule of thumb is to aim for a palm-sized portion of protein with each meal. It’s not just about quantity, however. Your body needs the right balance of amino acids, B vitamins, zinc and magnesium to actually break down and use that protein effectively.
"You could be hitting your “target” in grams but are still feeling tired, inflamed or are struggling with recovery. That’s why variety, digestion and nutrients all matter just as much as the number on the label."
Think "minimally processed, whole foods", says Pillai. "You can very easily meet your protein requirements if you include a good quality source of protein at each meal, such as eggs or Greek yoghurt at breakfast, chicken or edamame beans at lunch, and then prawns or chickpeas at dinner.
"If you are vegetarian or vegan, you may need to be more mindful to ensure your protein portions are large enough to meet requirements, as vegetarian protein sources are often slightly lower in total protein. There may be a place for higher protein products to help some people meet their needs, but often these products are ultra processed and there are healthier alternatives available."
Yes, it can be. "If someone has existing kidney problems, or is at risk of kidney stones, excessive protein intake — especially from animal sources — can further damage the kidneys in those with pre-existing conditions," Pillai explains.
"One sign is the digestive issues," says Pillai. "Often focusing just on protein can mean fibre intake suffers, which leads to a reduction in plant foods, and an increase in animal foods. This often leads to excess gas and bloating, especially if protein sources are via supplements."
The solution? "My advice would be to ensure you balance both protein and fibre in the diet, and vary the protein sources with plant sources so that you can reduce the possible digestive side effects."
Seeds, beans, berries, lentils, bananas, wholewheat pasta and bread, and chickpeas are all good sources of fibre that will keep you regular.
If you've noticed that you need to pee more often or your wee is a "darker coloured yellow", plus you're getting headaches and a dry mouth, then you might be dehydrated.
Pillar explains the science: "This is because excess protein increases the nitrogen in the body, and this needs to be excreted by the kidneys which increases the overall water loss."
Her advice? "Again, if you feel these symptoms, reduce protein intake slightly and ensure you are keeping well hydrated."
Often people up their protein intake when they start working out more — think the shakes and bars you spot people reaching for at the gym. Not an issue if you're moving enough.
However, "if protein consumption is higher than protein requirements, this will just serve as excess calories and will be stored as fat, leading to weight gain," Pillai explains. "This is even more so if the protein sources are high in fats, such as red meat and full fat dairy."
"Some women also find that if they focus on very low-carb and low-fat but high protein diets, this can impact hormone health, as fats and carbs are important for hormone production," Pillai says. "Thyroid function can also be impacted, as carbohydrates are required for the production of certain thyroid hormones."
"In some of these cases, I’ve seen raised kidney markers on blood tests, as well as symptoms like sluggish digestion, bloating, fatigue, or even skin issues; all of which can signal that protein is placing a strain on the system," Hamilton explains.
"It’s not always the protein itself that’s the problem, but the body’s ability to break it down and use it effectively. Without sufficient stomach acid, digestive enzymes, or co-factors like B6 and zinc, undigested protein can ferment in the gut, disrupt the microbiome and trigger immune reactivity or food sensitivities. It’s also worth noting that excessive protein can displace other nutrients like fibre, complex carbs, and healthy fats, which play equally important roles in energy, hormone regulation and gut health.
"It’s not just about the number of grams, it’s about the quality of your protein, how well you’re absorbing it and how it fits into the bigger picture of your health."
This article is not a substitute for medical advice. If you're at all worried about your health, especially if you have new symptoms, then book an appointment with your GP.
