Disruption of Sleep/Wake cycles adds stress to your body and can increase your chances of gaining weight because of hormonal imbalances, so make sure to get to sleep by 10.30pm
Keep the body moving. Even if you don't make frequent visits to the gym, try to stay active. Walk as often as possible and always take the stairs. It's no good, sitting in the office in one position all day and then fitting one hour at the gym in. The rule is to move regularly throughout the day. If you are in an office environment, try and get up out of your seat and walk around every half hour.
Burn your diet books, never diet, and never count calories.
Drink plenty of water, preferably half your body weight in ounces spread out through the day.
Eat high quality foods such as organic free range products, they have higher levels of nutrition and are free of pesticides.
Eat on a regular basis throughout the day, this will satisfy hunger. Include snacks in-between meals, this will elevate your metabolic rate.