The human race has a paradoxical energy crisis. We are drowning in stored energy (fat), something evolution did not prepare us for. Excess body weight now poses the greatest threat to healthy survival.
Most of the world's population lives in countries where overweight and obesity kill more people than underweight. Worldwide obesity has more than doubled since 1980. 42 million children under the age of 5 were overweight or obese in 2013.
No national success stories have been reported in the decades since these statistics have been collected. A growing body of research suggests we may have missed the most important part of the metabolic equation.
Until recently this problem was framed exclusively in a calories in - calories out model. More calories eaten than burned results in weight gain. This causal model defined the remedy. Decrease caloric intake and increase activity level. Any one who has followed this directive knows it is more complicated.
Recent discoveries have shown that a meal consumed at 8 a.m. is not processed the same way as an identical meal consumed at 8 p.m.. All mammals possess this metabolic circadian rhythm (changes that follow a 24 hour-cycle driven by environmental light and darkness) for good reason.
Energy requirements are defined by activity level. The human day (until recently in our history) consisted of an active daylight phase and a resting night phase. This resulted in the evolution of a metabolic day shift, so to speak, bearing little resemblance to the night shift. Daytime metabolism excelled at eating, energy harvesting and storage while nighttime metabolism was designed for fasting and accessing stored energy. Melatonin, the body's expression of darkness, orchestrates these changes.
Traditionally, melatonin was considered primarily as a sleep cue. It is now recognized as the most powerful messenger to switch from active to resting metabolic function, a chemical signal of day's end. Darkness triggers the secretion of this ancient hormone. Light, whether natural or artificial, blocks melatonin secretion.
The widespread adoption of electric lighting ended sunlight-entrained human circadian rhythms. Illuminated night blocks the natural transition to a fasting state. Energy (calorie) acquisition and storage continue. Even dim light at night has been shown to significantly decrease melatonin secretion in humans. This disconnection from nature's clock is now considered an important cause of our struggle with weight gain.
Melatonin exerts its effect on weight by modulating the action of several key metabolic hormones such as insulin, ghrelin and leptin. These hormones orchestrate appetite, satiety, calorie uptake and fat storage. It also appears to increase activity level and core body temperature thereby increasing energy expenditure. Investigators believe this increased calorie usage is due to activation of brown fat. Unlike white fat (most body fat) that stores energy, brown fat burns up lots of extra calories by producing heat.
Animals who have had the pineal gland (location of melatonin production) removed become overweight. Timed administration of melatonin reverses the weight gain. In addition, middle-aged fat animals given melatonin and studied to old age showed decreased weight and visceral fat. These changes were eliminated if melatonin was withheld.
So what can you do with these findings?
Here are three ways you might jumpstart weight loss while working on your food choices and activity level.
1. As the saying goes, "Eat breakfast like a king, lunch like a prince, and dinner like a pauper." (Try to have your biggest meals during daylight hours and minimize eating after dark.)
2. Try to use dimmer light one to two hours before bedtime. Make sure your bedroom is as dark as possible. Eliminate even low lighting from cell phones, computers and other devices.
3. Speak with your doctor about a trial of melatonin even though it is a supplement available over-the-counter. Remember that the timing of the daily dose (one to two hours before bedtime) is central to its efficacy.