Too little sleep or too much sleep can throw your stress and regulatory hormones out of whack, and may lead to weight gain. A single night of sleep deprivation can increase levels of ghrelin (a hormone that promotes hunger), making you more likely to overeat the next day. Reduced sleep may also lead to fatigue during the day (duh) and less physical activity, which may be another reason why people who regularly don't get enough sleep tend to gain weight.
It’s natural for anyone trying to lose weight to want to lose it very quickly. But evidence shows that people who lose weight gradually and steadily (about 1 to 2 pounds per week) are more successful at keeping weight off. Healthy weight loss isn’t just about a “diet” or “program”. It’s about an ongoing lifestyle that includes long-term changes in daily eating and exercise habits.
"If your diet consists of lots of sports drinks, sugar-sweetened drinks like fizzy pop and flavoured waters, or sugary foods like chocolate and cakes, it will make losing weight harder. While whole fruits and vegetables are undoubtedly good for you, they can also sometimes cause weight gain if you eat too much, as they have high levels of natural sugars in them. Low-fat food options might have high amounts of added sugar in there too, so make sure to check the food label.