The art of getting proper fuel is not just a simple input/output equation. Yes, in general: eating sufficient macros (fats, proteins and carbohydrates) and micros (vitamins and minerals), as well as steering clear of processed foods, is key to replenish calories expended during the day. We all know what you eat matters. But the latest research also shows that when you eat is just as important.
According to Dr. Nada Milosavljevic, MD and Director of Integrative Health at Mass General Hospital, your body's internal clock, a.k.a. circadian rhythm, greatly impacts how you make food choices and metabolize fuel. With a little knowledge and awareness, you can tweak your eating habits to sync with your circadian cycle, which in turn supports weight-loss efforts. (Yep, you read that correctly—eat at the right times, and it may help you to shed those stubborn lbs.)
How Your Body's Circadian Rhythm Impacts Metabolism
The process by which our body breaks down and uses food is called metabolism. "Metabolism isn't just what happens in your stomach," says Dr. Milosavljevic. "It refers also to a wide range of biochemical processes that are going on. So something that impacts your metabolism has a huge influence on your overall health and wellbeing." A big driver of metabolism just so happens to be the hormone called cortisol.
Your circadian rhythm triggers cortisol, often known as the stress hormone, or the "get up and go" hormone. Cortisol supports thyroid function and metabolism, and contributes to the energy you need to complete your daily activities.
The Circadian Rhythm Diet: It's Simple—Eat 7-7
Enter: eating with the sun cycles.
"Because your metabolism is receiving a jumpstart from cortisol, the food you consume when cortisol is released has a greater likelihood to be burned and turned into fuel, rather than stored as fat," says Dr. Milosavljevic. Your body naturally releases cortisol twice per day: once in the early morning, and once again in the late morning. The opposite is true in the evening. When the sun sets, your body naturally wants to winds down and prepare for sleep. Part of that winding down is your body's response to lower cortisol levels so you're not on the go. If you consume food later at night when your cortisol levels are decreasing, it's more likely to be stored as fat. But by syncing up your diet to eat early in the day, and stop eating early in the evening (avoid those late-night snack binges!), your circadian rhythm can help regulate how those calories are used.
"Using your body's own natural cycle to shape your eating habits can enhance weight loss efforts, and consuming food between approximately 7 a.m. and 7 p.m. is the optimal time for your body's needs," says Dr. Milosavljevic. "Knowing this, you should leave your midnight snacks behind and ride the circadian rhythm wave and cortisol peaks to maintain good eating habits that align with your body's natural inner clock."