Day 30 – When’s the best time to eat?

Day 30, and our final day of our Bitesize Nutrition challenge is about timing.

In the last 50 years we’ve started to eat later in the day, less breakfast, and more snacking.

Body clock

You’ve probably heard of circadian rhythm – it’s a central clock which dictates the sleep-wake cycle. There are further clocks in various organs and tissues throughout the body influencing metabolism, digestion, hormones. These clocks take signals from our environment e.g. daylight and meal times. Altering these can cause confusion.

When body clocks are disrupted, the pancreas is one of the organs which starts to function incorrectly. Glucose remains in the blood and not in muscles leading to feelings of fatigue – the natural response is to reach for the processed carbohydrates (cakes, biscuits, sweets etc) as an energy boost, but the more of these you eat the more insulin is released….so the vicious cycle continues….

It’s thought that eating earlier and not late allows the body to more easily digest food – during daylight (natural light) hours rather than eating with artificial light. Eating later in the evening could increase the risk of obesity and poor blood sugar control.

A small (13 people), 10 week University of Surrey study shifted breakfast 90 mins later and dinner times 90 mins earlier and found reduction in participants body fat. Despite unlimited access to food during non-fasting hours, total calories were less. Further data suggests to reduce body fat focus should be towards intermittent fasting (fasting for 12-16 hours) as potentially beneficial. Read our article (day 17) for more on this.

Breakfast like a king

It’s an old adage – breakfast like a king, dinner like a pauper, but does it still hold true? Some studies including a large (50,000 people) US study over seven years identified people who ate larger breakfasts had lower BMI than larger lunch or dinner eaters.

Female participants lost 2.5 times more weight when consuming most calories at breakfast compared to more calories at dinner (same total calories), but could their breakfast be part of a wider healthier lifestyle, therefore biased results?

Children’s academic performance is suggested to be improved following breakfast. By 10am children who missed breakfast began to notice energy and concentration flagging affecting behaviour. Perhaps behaviour could also be affected by lack of sleep as a contributory factor?


There’s some interesting research emerging about intermittent fasting to assist in maintaining a healthy amount of fat, however longer and larger human studies are required before this can become more prescriptive. Intermittent fasting is not advisable for children, elderly, pregnant women, type-2 diabetics, history of eating disorders without advice from their health professional.

What you eat remains more important than when you eat.

If you’d like to find out more tips to improve your health, check out our webinars and our Bitesize Nutrition podcast with Dr Adam Collins on timing of meals around exercise. If you’re new to podcasts you can listen free without registration on your phone or PC by clicking on the podcast link in this paragraph. Or you can listen to Bitesize Nutrition on iTunes & Spotify.

Don’t forget to let us know what you think using #nutritionchallenge30

A reminder:

  • The information in this article is for educational purposes and should not replace medical advice.
  • The information is not intended to diagnose or treat any medical condition.
  • If you have a diagnosed medical condition, you should consult a doctor before making any major changes to your diet, and;
  • Some supplements may interact with medications and you should check with your GP before commencing any supplement programme.

Jakubowicz, D 2013 High caloric intake at breakfast vs dinner differentially influences weight loss of overweight and obese women

de Castro JM. The time of day and the proportions of macronutrients eaten are related to total daily food intake. Br J Nutr 2007;98:1077‐1083.

Leidy HJ, Bossingham MJ, Mattes RD, Campbell WW. Br J Nutr 2009;101:798‐803.

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