We should not eat carbohydrates or consume calories before exercise as it will cause weight gain and will cancel out what we have burnt while exercising.
We need calories (energy) to fuel activity. The key to preventing weight gain is to be calorie deficient. Calories not taken with increased physical activity may induce muscle loss. This reduces rest metabolic rate and overall calorie requirement.
Potassium is the most critical electrolyte for training
Sodium is the primary electrolyte (mineral). It is required before, during, and after a sweaty workout. Hence drinking sports drinks or electrolytes with sodium is good.
Sports drinks are for endurance athletes or for training over one hour. Those who do weight or strength training do not require it.
Sports drinks provide both fluid and electrolytes for hydration, as well as carbohydrates for energy. Regardless of duration or type of training, one should consume drink fluid during training to limit weight change to about 2%
Protein improves performance when it is consumed during exercises. So one must drink protein during training especially weight or strength training.
Protein before or during exercise does not provide any additional benefit. In fact, protein slows down gastric emptying and hence reduces the feel for fluids and electrolytes. It is better to consume protein after exercise as protein helps muscle synthesis.
Protein Isolate is the nest of protein for recovery. Hence one must give it preference over all other forms of protein.
Protein products come as concentrates, isolates, and hydrolysates. Concentrates have low levels of fat and other nutrients. Isolate is processed to remove fat and hence give higher protein per gram with minimum calories. Hydrolysates are proteins broken down into smaller molecules for quicker absorption. Dietary protein is the best followed by any other but does not consume 20 to 25 grams of protein in one meal.
While training we only lose water.
If that was so, sweat will not taste salty and there will be no cramps because of excessive sweating. Sweat contains sodium, chloride, potassium, magnesium, and many other minerals. Hence sweating will result in mineral losses and needs to be compensated by certain drinks.