It’s not uncommon for people to be confused about when to eat, especially with all the different fad diets in the world that have conflicting rules. There is no magical secret about when to eat. It’s about following the science of our body’s internal clock – aka the circadian rhythm. The circadian rhythm controls our energy levels, our wake/sleep cycle, and our blood sugar level (among other things). The human body is tightly regulated and while our circadian rhythm can be disrupted by day-to-day life, it can also be retrained to work optimally. Disruptions to the circadian rhythm can affect our health by increasing the risk of obesity, diabetes, depression, and other chronic health conditions.

Structured eating supports our body’s circadian rhythm, promotes a healthy weight, and helps maintain stabilized blood sugar levels. Our body goes into a natural fast overnight while we sleep making it important to consume our first meal or snack within the first hour or so of waking up to break this fast and get the metabolism started for the day. After that it is ideal to eat every 3-4 hours to keep blood sugar levels stable throughout the day. This allows us to provide small amounts of fuel every few hours to allow our bodies to do the work that needs to be done throughout our daily lives – this prevents us from feeling tired or cranky.

There is often misconception about eating in the evening – it is okay to eat in the evening but be mindful of food choices and portions. Regardless of the time of day you eat, if you overeat there will be an increased release of insulin and an increased risk of energy being stored as fat. Ideally, have your last eating event at least two hours before bed to allow for digestion and to prevent reflux while sleeping. Our body can only absorb so many calories/nutrients at once providing another reason to eat often throughout the day, to optimize absorption of nutrients for our bodies to utilize. Another fun fact to keep in mind is the thermic effect of food, the calories used to digest food – you burn more calories eating five times per day compared to twice per day.

Grazing, however, is eating too frequently, and is not beneficial for our body or health. This can be eating every 1-2 hours or unplanned repetitious snacking on small amounts of food throughout the day. Most often grazing is related to the composition of what was eaten last – most people tend to graze on carbs or empty calories. Carbohydrates are digested quickly and if consumed alone or there is too much in the meal/snack it can lead to someone feeling hungrier sooner, and if they choose to munch on more carbs the cycle can continue (blood sugar goes up and down). This eventually leads to overconsumption of calories throughout the day and can prevent someone from getting the proper amount of other nutrients within their diet as well. Grazing can also happen from skipping meals, eating out of boredom/stress, food deprivation or mindlessness.

Besides paying attention to the timing of meals/snacks, it’s important to pay attention to composition and amount of food. The amount of food needed will vary from person to person based on their individual body. For meals and snacks it’s ideal to include all nutrients – carb, protein, and fat – to promote a balance of ingested nutrients, stable blood sugar, optimal nutrient absorption, and digestion. Retraining the body to eat according to the internal clock takes a little bit of practice and patience, but once you’ve adjusted, your body will regularly tell you when you are hungry, and it will also let you know when you are full.


Danielle Johnson RDN, CDN, CPT, RYT is a registered dietitian who works in the Department of Bariatrics Center of Excellence at Mather Hospital, where she specializes in surgical weight loss and medical weight management. She is also completing her Master of Science in Integrative Nutrition at Stony Brook University.