Are there any side effects (e.g. overdose)?

In general, it is not necessary to exceed the dietary recommendation of 0.8 g protein per kg body weight per day if no competitive sports are being practiced or if there is any other exceptional situation for the body. The additional proteins taken in are broken down by the body into their individual parts, the amino acids, and converted into sugars or fat and stored as such. This might also be of interest to you: Amino acids and sports

For a long time, it was believed that overdosing of proteins could damage the kidneys in the long term, as the protein components in the blood could, in the long term, impair the kidney‘s filter units.
The kidney must constantly work harder than usual to remove the proteins from the urine and renal insufficiency can develop. In the meantime, however, several long-term studies have come to the conclusion that such a correlation cannot be clearly proven. Many of the previously conspicuous kidney damages had other or different causes.
In addition, weight gain can occur because protein bars are very energy-rich due to their high protein and sugar content.
In addition, a diet high in protein and low in fiber can lead to digestive disorders such as flatulence or constipation.
The artificial sweeteners contained in many protein bars, on the other hand, can have a laxative effect if consumed in excess.

Are bars better than shakes?

Just like protein bars, protein shakes are popular with athletes who want to increase their protein intake to build muscle. There is also a large selection of shakes, geared to the most diverse needs and demands. In general, athletes tend to use protein shakes after training, and rightly so.

Depending on the manufacturer, protein shakes contain 30-40 g of protein per serving, whereas most protein bars contain about 16-20 g. In addition, the protein powder for shakes is easier to dose, which means that the protein content can be further increased according to individual needs without increasing the volume. Many protein bars contain ingredients such as nuts, chocolate, dried fruits or caramel that increase the sugar and calorie content and make the bar more of a candy than a healthy supplement. Bars consumed in excess can therefore lead to weight gain and should be considered as a luxury food rather than as part of the daily diet.In addition, many bars contain inferior proteins, such as soy protein, which should not be consumed in excess, especially by women, due to the chemical similarity of ingredients to estrogen. In addition, a protein called collagen hydrolysate is contained in some bars, which has only a low biological value for the body and therefore does not contribute to muscle building. Therefore, if an increased protein requirement is to be met with a dietary supplement, a protein shake is more recommended, while a protein bar is more suitable as a candy from time to time.