My vote is sleep. Sleep helps rejuvenate the body and balances your hormones to use energy from fat. Inadequate amount of sleep has been linked to weight gain.
If you have trouble falling asleep, try these exercises to put your body in alignment so you can get a little more shut-eye. Restorative exercises like these trigger the parasympathetic nervous system to activate the relaxation response.
Do them before nodding off to bed.
Step 1: Butterfly
Take two large towels and fold them in half, then roll them into a cylinder. Lie on the ground with one towel between your shoulder blades and supporting your heart and the other towel just below your belt line.
Bring the bottom of your feet together with knees to the sides and arms open. Take 10 deep breaths and relax the body.