"Eat less, exercise more" is, according to know-it-alls all over the internet and in your life, the sole answer to weight loss. Often thrown about to taunt those who struggle with losing weight, this mantra sounds oh-so common-sense — but it's deceptively so, and "sounds" isn't the same as "is". Weight loss is, after all, influenced by numerous other factors. What you eat, when you eat, how you exercise, and other things such as medications you may be on, all also influence a person's ability to successfully lose weight.
How Much Sleep Do You Really Need?
- Teens require between 8 and 10 hours of sleep a night.
- Young adults between the ages of 18 and 25 need 7 to 9 hours of sleep.
- Adults between 26 and 64 generally do best if they get 7 to 9 hours of shut-eye, too.
- 65-plussers, on the other hand, need less sleep: between 7 and 8 hours. 
Having said that, we're all unique individuals, and our sleep needs do vary. While some people in the "adult" category really do better on 6 hours of sleep and there's also "sleepy-heads" who need 10 hours, the National Sleep Foundation doesn't recommend less or more sleep than those outlier-hours. (They refer to actual time spent sleeping, not time in bed!) 
Everyone's heard the "eight hours a night" mantra, and though this isn't strictly speaking appropriate for everyone, it's a guide to start off with. Research, unfortunately, reveals that about a third of US adults are chronically sleep-deprived, resulting in such things as having trouble concentrating, memory loss, decreased work performance, and even difficulty driving!  Chronic sleep-deprivation leads to more than short-term annoyances, however — it's been linked to high blood pressure, heart disease, stroke, kidney disease, and type 2 diabetes too. 
OK, Poor Sleep Habits Are Bad, But What On Earth Has This Got To Do With Weight Loss?
Circadian rthythms are bodily systems governed by an internal "biological clock". Your sleep-wake cycle is one example, but metabolic processes as glucose, insulin, ghrelin, and leptin levels are also dependent on circadian rhythms. In case you're not familiar with the last two terms, they're hormones that are responsible for regulating... you guessed it: your appetite. .
It is no surprise, then, that studies have found that people who get the recommended amount of sleep lose weight, specifically fat, more easily than their sleep-deprived counterparts , while people who sleep for abnormally long periods of time are also at a higher risk of obesity .
While your body itself starts working against you when you're getting the right amount of sleep, as we've seen, you yourself also contribute.
We've all been there — whether we've not had enough sleep or have overslept, we end up with a fatigued, groggy feeling that doesn't provide optimal circumstances for productivity, to say the least. To combat this unpleasant feeling, we may resort to eating and drinking, especially things with sugary contents or processed carbohydrates that we instinctively see as a quick fix for more energy. Indeed, research has shown that those people who lack sleep tend to over-eat, consuming around 600 calories more than they would have if they'd slept for longer [10, 11].
In a more rested state, your internal dialogue might go something like: "Hold on, you're on a diet! Do you really want that bag of crisps and that energy drink?" While you're sleep deprived, however, those parts of your brain that would otherwise keep you on track aren't working as well, leading you to succumb to those cravings more easily. 
Then, there's another obvious way in which not being well-rested can interfere with weight loss — when you feel fatigued, you are much less likely to stick to those exercise plans you made and instead stay in bed, on the couch, or at your desk. Poor sleep contributes to a sedentary lifestyle, in other words.
The Bottom Line
You know what I love about working on my weight? The fact that it's not just about weight loss! My own weight loss diet has led to all kinds of interesting rabbit trails, all of which ultimately contribute to better overall health as well as an improved weight. If you, too, are on a weight loss diet, reexamining your sleep hygiene may well help you along the way, as well as reducing your risk of stroke, heart disease, and kidney disease.