Protein: how much to consume and the health effects of excess

Protein bars, pasta, gelato and even protein water are becoming increasingly common in the fitness market. As these products, which promise to boost nutrient intake, grow in popularity, experts explain that protein requirements must be assessed individually and that consuming too much does not necessarily bring greater health benefits.

The warning comes amid rising consumer interest in the nutrient, also driven by the food industry’s marketing strategies. A recent Atlas/Intel survey found that 3 in 10 Brazilians are influenced by a protein label when buying a product, while 37.9% of respondents said social media encourages them to consume these items.

Although protein is essential for functions including muscle maintenance and growth, the production of enzymes and hormones, and immune system function, the right amount depends on factors such as age, weight, level of physical activity, goals and health conditions. For this reason, the nutrient should be considered as part of the overall diet, rather than as the sole measure of a product’s or diet’s quality.

“There is no maximum amount of protein that the body can absorb and metabolise per day or per meal. These figures must be assessed according to each patient’s clinical and metabolic context. What may exist is a limit to the stimulation of muscle protein synthesis,” explains Monize Aydar, an Omint-accredited nutrition physician.

How much protein should you consume?

According to Monize Aydar, for adults, around 0.25 to 0.40 grams of protein per kilogram of body weight per meal generally maximises the muscle protein synthesis response. For most people, this usually equates to roughly 20 to 40 grams of high-quality protein. Higher amounts, however, are still used by the body for other purposes, including the synthesis of enzymes, hormones, plasma proteins and immune cells, and can also be used to produce energy when required.

For healthy people seeking anabolism - the process of building and repairing muscle - and longevity linked to strength training, the nutrition physician says daily intake can generally range from 1.2 to 2.0 grams of protein per kilogram of body weight, spread throughout the day. This guidance must nevertheless be personalised according to each person’s age, clinical status and goals.

Health effects of excess protein

Potential consequences of high-protein diets include increased calorie intake, which may contribute to weight gain when there is an energy surplus; replacing foods rich in fibre, vitamins and minerals; increased urea production, reinforcing the importance of adequate hydration; and poorer metabolic control when the dietary pattern relies on ultra-processed meats and foods high in saturated fat. “In predisposed individuals, unsuitable intake may also be associated with a higher risk of kidney stones, gout attacks, acne, depending on the protein source, and gastrointestinal symptoms,” says the nutrition physician.

Extra care is needed for certain groups, including people with non-dialysis chronic kidney disease, particular liver diseases and other clinical conditions requiring specific dietary restrictions. Patients with a history of kidney stones, gout or acne may also need individual monitoring to determine the most appropriate protein source and amount.

When does increasing protein make sense?

With an ever-expanding range of protein-enriched foods, consumers may end up adding several products throughout the day without realising they have already met their requirements. Yoghurts, manufactured bars, protein coffees and protein desserts can have a place in the diet in specific circumstances, but they are not necessarily essential for most people.

For Dr Lara Natacci, an Omint-accredited nutritionist, protein should be only one of the criteria considered when selecting a food. “Protein matters, like any other nutrient, but it should not be the only selection criterion. Many products are marketed using this appeal, yet they may also contain large amounts of sugar, saturated fat or salt,” she warns.

For most healthy people, daily protein needs can be met through a balanced diet without relying on supplements. Animal-based sources include lean meat, chicken, fish, eggs, milk and dairy products. Plant-based choices include pulses such as beans, lentils, chickpeas and soya.

“Supplementation can be useful when food alone is not enough to meet an individual target, such as in some cases involving older people with a poor appetite, athletes with high requirements, people recovering from illness, or individuals with specific dietary restrictions. Even then, a supplement should serve as an addition, rather than a replacement for a varied diet,” the nutritionist stresses.

More protein does not mean more muscle or weight loss

Another common misconception is that simply raising protein intake is enough to lose weight or gain muscle mass. For Dr Lara Natacci, the nutrient is an important component, but it does not work in isolation.

Weight loss requires consideration of energy balance and the overall quality of the diet, as well as regular physical activity, adequate sleep and stress management. To gain muscle mass, sufficient protein intake must be combined with the stimulus provided by strength training.

“Without this stimulus, the body will not be able to build muscle, even if someone consumes a large amount of protein. Other related behaviours need to be in place,” she explains.

According to the nutritionist, the key point is not to view protein as the main ingredient on the plate, but as one part of it. A healthy diet relies on a balance of all nutrients, including quality carbohydrates and good sources of fat. In this context, rather than following trends or seeking out high-protein products, it is more important to understand personal needs and establish a varied eating routine that supports health in a comprehensive and sustainable way.

By Thais Santos