Day 30, and our final day of our Bitesize Nutrition challenge is about timing.
In the last 50 years we’ve started to eat more food later in the day and less food at breakfast, coupled with irregular meal times.
You’ve probably heard of circadian rhythm – there’s one central clock which is the sleep-wake cycle and controlled by the pituitary gland. There are further clocks in 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 with reduced insulin secretion leading to increased blood glucose levels (type-2 diabetes and obesity). Glucose remains in the blood and not in muscles meaning greater feelings of fatigue – the natural response is then to reach for the processed refined 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 not eating too late in the evening means the body is more able to digest carbohydrates – 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.
Don’t forget to let us know what you think using #nutritionchallenge30
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.