Sleep can be a deciding factor in fat loss. In fact, you can do everything right in terms of diet and exercise but if your sleep quality and sleep quantity don't match your goals, your results will be disappointing.
The less rested you are, the less self-discipline you have, so choices that were once easy (eating the reasonably tasty and healthy lunch you packed for yourself vs. ordering pizza) are now difficult. In addition to limiting your ability to make good choices, less sleep makes you hungry. It prompts you to eat more when your body doesn't need it. This is why sugar is so fattening -- sugar calories are "phantom calories" that your brain doesn't register in regulating your appetite.
Lack of sleep seems to directly and negatively affect your metabolism. You can take two groups of people doing the same diet and exercise program, but cut one group's sleep in half and that group will lose 50 percent less fat, plus lose 50 percent more lean body mass.
In our society we all seem to be time-crunched, especially those with children. The good news is that you may not necessarily need to devote a lot more time to sleep. Eight hours of relatively poor sleep will still leave you looking and feeling like crap, while six hours of great sleep can have you feeling like a million bucks. The bad news is that most people can't really look and feel the way they want with less than six hours of quality sleep.
How to improve sleep quality
1. No TV or work in bed. You want your bed to be a place of sleep. You don't want your body to associate the bed with mental stimulation like TV and work. If you watch TV in bed over and over, your mind will associate the two, conditioning your mind to be "on" in bed, which kills sleep quality.
2. Consistent wakeup and bedtime. Sure, it feels good to sleep in four hours on Sunday. But the older you get the more likely that late wakeup time means you're going to lie awake half the night Sunday and wake up like a zombie Monday. Restful sleep requires you to be tired at the end of the day. If you're awake for only 12 hours, and not doing much, then your sleep (and fat loss) will suffer.
3. No caffeine after a certain point in the day. For men it is 4 p.m. For others, it's noon. Caffeine prevents sleep no matter how tired you are.
4. Work out. Full exertion is necessary for full relaxation. Even when you have trouble sleeping (and are pooped) you need to exercise -- expend more energy so that your body can actually sleep later.
5. Get some full-spectrum light bulbs for the daytime. It seems that there are some light receptors in your eyes that aren't responsible for vision, but rather for keeping time. There are certain parts of the visible spectrum that seem to help your body know if it is daytime. Almost all normal light bulbs are lacking those portions of the blue and violet visible light, so for many people the body doesn't really know if it's daytime or nighttime. This is a really cheap and easy fix. Just do not put them in your bedroom.
6. Keep your bedroom dark and quiet. Cellphone off. Get good curtains, and generally remove things that make noise or emit light.
7. Do some breathing exercises to push your body into relaxation. Most people end up breathing from their necks during the day, which puts your body on alert and hinders good sleep. Your breath is one of the most direct routes to balancing out your body.
This is really simple, and you can do it as you lie in bed: Put one hand on your chest and place the other hand over your navel. Breathe so that your collarbone does not move at all, and that your belly button does. Do this until you feel relaxed (usually five minutes).