According to Harvard Health, for most dieters, preventing the pounds from coming back after working so hard to lose them, is the biggest challenge. On average, people regain two-thirds of the weight that they’ve lost within two years. One way people try to prevent gaining (or regaining) weight is through daily weigh-ins. On one hand, this idea makes logical sense. When the number on the scale starts to increase, you know it’s time to tighten up the diet and/or hit the gym more.