An excessive consumption of sweets leads to obesity unless the energy obtained is used up.

Be sure to do some exercise to burn off the excess energy you'll get from eating sweets.

People get fat as a result of eating far too many sweets and doing nothing energetic at all.

If a person eats too many sweets but doesn't burn the energy thus given, he'll become obese.

Obesity comes about because far too much sugar is consumed to be able to use the extra energy.