Low-carb diets can drain your energy. Coupled with an increased protein intake, a low-carb diet will likely help you lose weight when you reduce your total calorie intake. However, a few problems can arise if your carb intake is too low, since carbs are the main source of energy for your body – and your mind. To avoid negative side effects associated with eating too few carbohydrates, aim to consume the recommended dietary allowance, or RDA, for carbohydrates on a daily basis.