Protein: when more is not better for health and muscle

Protein bars, pasta, gelato and even protein water have become increasingly commonplace in the fitness market. As these products promising to boost nutrient intake grow in popularity, experts explain that protein requirements should 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 industry’s sales 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 motivates them to consume such items.

Although protein is essential for functions including maintaining and building muscle, producing enzymes and hormones, and supporting the immune system, the appropriate amount varies according to factors such as age, weight, level of physical activity, goals and health conditions. It should therefore 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 need to be assessed according to each patient’s clinical and metabolic context. What may exist is a limit on 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 equates to roughly 20 to 40 grams of high-quality protein. Higher amounts, however, are still used by the body for other roles, including the synthesis of enzymes, hormones, plasma proteins and immune cells, and can also be used to produce energy when needed.

For healthy people aiming for anabolism - the process of muscle building and repair - and longevity associated with 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. The recommendation must nevertheless be tailored to each person’s age, clinical status and goals.

Effects of excess protein on health

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

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

When does increasing protein intake make sense?

With a growing range of protein-enriched foods available, consumers may add various products throughout the day without realising they have already met their requirements. Yoghurts, manufactured bars, protein coffees and desserts can have a place in the diet in specific situations, but they are not necessarily essential for most people.

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

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

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

More protein does not mean more muscle or weight loss

Another common misconception is that increasing protein alone is enough to lose weight or gain muscle mass. For Dr Lara Natacci, the nutrient is an important part of the equation, but it does not work in isolation.

For weight loss, it is necessary to consider energy balance and the overall quality of the diet, alongside regular physical activity, sufficient sleep and stress management. To gain muscle mass, adequate protein consumption must be combined with the stimulus provided by strength training.

“Without that stimulus, the body will not be able to build muscle, even if the person consumes a large amount of protein. Other associated behaviours are important as well,” she explains.

According to the dietitian, the key point is not to view protein as the main component of the plate, but as one part of it. A healthy diet depends on a balance of all nutrients, including quality carbohydrates and good sources of fat. In this context, understanding individual needs and building a varied eating routine that supports health comprehensively and sustainably matters more than following trends or seeking out high-protein products.

By Thais Santos