Although your body isn’t an actual watch, it does have an internal clock that runs approximately every 24 hours. This “circadian rhythm” keeps your body functioning on a schedule. It helps your body adjust to environmental changes, sleep, and behaviors like eating.
It’s clear that what foods you eat can affect your body. But when you eat can also have an effect. The timing of your meals and snacks can affect:
- metabolic regulation
- body-weight regulation
- management of obesity-related diseases
- sleep cycle
Read on to learn about what science says about your circadian rhythm and eating habits, and how they impact each other.
Trying to figure out the best time to eat can be confusing, and researchers are looking to see if there are answers. One study
What about breakfast?
Research shows mixed results as to whether breakfast intake contributes to weight loss. One study found that people who ate breakfast saw reduce dietary fat intake and impulsive snacking. Another study found that people who ate more calories at breakfast didn’t necessarily eat less during the day. Breakfast patterns have a smaller role in daily intake than post-breakfast meals.
After reviewing studies regarding breakfast’s impact on weight, the United States Department of Agriculture recommends that people eat a nutrient-rich breakfast to help manage weight and improve overall nutrient intake.
The connection between the body’s natural biorhythms and weight gain is more than just what you eat. Restricting what you eat to a certain time every day sets your body on a schedule. Research
Regular meal times also play a long-term role in body weight. Your body generally gets hungry every three to five hours, but it’s also used to your regular schedule. Try to eat at the same time every day. You can keep healthy, high-satiety snacks like vegetables and cheese around to eat between meals to curb your appetite.
In some cases of meal timing, switching when you eat bigger meals can make a difference. One
Sleep loss disrupts your body’s internal clock and metabolism and can affect hormonal balance. Research
One study found that mice who were exposed to light at night gained 50 percent more weight than mice who had truly dark nights.
Why do we tend to snack at night?
We often think of diet as the quality of the food we eat, but it really also includes when you eat. Research
The “night owls” who got less sleep overall had:
- more fast food
- more soda
- fewer fruits and vegetables
- larger portions of food later in the day
Overall, they ate about the same amount of calories per day as people who slept normally, but calories consumed after 8:00 p.m. are more strongly associated with weight gain.
If you exercise regularly and want to maintain lean mass, you may be interested in intermittent fasting (IF). IF is different from eating on a regular schedule, as you restrict your energy intake to certain time periods of the day. This study saw a decrease in fat mass and weight for people who practiced 16-hour fasting with an eight-hour eating window along with resistance training.
Research shows that IF can:
- have similar effects as intensive exercise
- reduce resting heart rate
- reduce blood pressure
- help with weight loss
- decrease risk of coronary artery disease
- suppress appetite
How to fast
One popular method of IF is the 16/8 fast, meaning you fast for 16 hours every day and restrict eating to an eight-hour window. For example, if your last meal was at 11 p.m., you wouldn’t eat until 3 p.m. the next day. But this method of weight loss on its own may not be as effective without exercise.
You may need to fast for three to four weeks before you see measurable results.
Potential side effects
Fasting can lead to vitamin deficiency and muscle loss if you’re not careful about what you eat. But you can also address these concerns with proper nutrition and strength training.
In general, intermittent fasting may not be right for your lifestyle. You may also find it hard to not eat for a lengthy amount of time or to avoid eating during social situations.
Calorie restriction is believed to be the most effective method of weight loss, but when you eat may affect how your weight loss journey goes. The recommended route to managing your food intake is to have an eating schedule that suits your lifestyle. You may find a food journal helpful to avoiding mindless eating.