Quick and Short version
Your body’s circadian rhythm is essentially your body’s own clock. Disruption of the circadian clock can alter biochemical, physiological, and behavioral circadian effects.
Studies were done when mice were given food exclusively during the day, their actual circadian rhythm and metabolism started to change. Further studies have shown that these alterations in normal feeding patterns resulted in greater food or calorie intakes and in the long term, elevated body weight and unhealthy metabolic parameters. For example, when mice were housed in constant bright light, they consumed more food and calories. However, when switched back to their natural light/dark rhythm, their calorie intake reduced.
Several studies have demonstrated significantly higher risk for developing obesity and diabetes with short sleep duration (<5 hours) or late sleeping patterns (midpoint of sleep > 5:30 AM). These studies have also found that individuals tended to eat later dinners and consumed more calories late in the evening.
In a 2013 study, eating late led to a decrease in effectiveness and success of a weight-loss intervention. Most interesting of all, both groups of subjects had similar characteristics: age, appetite hormones values, energy intake, sleep duration and macronutrients distribution.
Finally, in a controlled study using 32 young lean women, researchers found that after 1 week of eating late (lunch at 4:30pm), the women suffered from metabolic alterations that play a role in obesity, such as blunted variations in cortisol and body temperature, decreased blood sugar tolerance, decreased resting energy expenditure and decreased carbohydrate utilization.
These findings were in comparison to a similar week where lunch was provided at 1pm.