Too Few Calories Causes Slow Weight Loss
Many dieters see food and calories as the enemy of weight loss. So they think the fewer calories they eat, the more weight they will lose. One reason why fad diets like the Cabbage Soup diet and Grapefruit diet are so popular. Unfortunately, although we do need to restrict calories if we want our body to burn its stored fat, we can't afford to eat too little. Why not? Because this sends a signal to our brain that food is scarce and convinces it to conserve calories. As a result, we stop burning calories as fast as normal, which leads to slower weight loss.
Source : Diet-I