One is about 200 calories, 20 grams of protein and 4 grams of carbohydrates (not counting fiber).

If it is strength training, basically practice for one or two hours at a time, and eating one is enough. 20 grams of protein is enough.

If it's to reduce fat, I personally think it's better not to eat. ...

In fact, to put it bluntly, it is to calculate heat. If you add muscle, your intake will be greater than your expenditure. On the contrary, if you subtract fat, your protein intake is at least 1.5g/kg, and it is better to be 2.5g/kg.

Finally, the absorption efficiency of protein bars is actually not as high as that of protein powder. The main purpose is portable, so if it is to gain muscle quickly after training and supplement protein, protein powder is better.