A study by Columbia University found that people who don't get enough sleep consume an average of 300 more calories a day than those who get enough sleep. What is more striking is that women are more likely to get fat than men if they stay up late. Because the study found that women who don't get enough sleep consume 329 calories more every day, while men consume 263 calories more. The metabolic rate of women's bodies is lower than that of men, and these extra calories due to staying up late are likely to make women who stay up late fat. Eating 329 calories more is equivalent to eating half a meal every day.