In New Zealand, 370,000 people live with osteoarthritis and international research suggests that 90% of osteoarthritis patients are obese. Obesity is the number one modifiable risk factor for osteoarthritis, with a 10% reduction in body weight leading to a 50% improvement in pain and function (see earlier article here for more information on the beneficial effects of weight loss in osteoarthritis). We are becoming more aware of the benefits that weight loss brings, however successively losing and maintaining a healthy weight for most remains elusive. Making significant modifications to our diet is often met with limited success and now more than ever there is confusion and mistrust around optimal dietary approaches for health and weight loss. The majority of dietary research in the field of weight loss has focused on interventions to either chronically reduce an individuals energy intake (calorie/kilojoules) or manipulate macronutrient composition of the diet (carbohydrate, fat, protein).

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An emerging area of research that has been outlined in recent reviews by Hawley et al and Parr et al (see recommended reading) is the concept of Chrono-nutrition, which focuses on the duration of time an individual eats over the course of the day (hours from our first to last eating occasion). Chrono-nutrition focuses on optimising our circadian biology which has been considerably disrupted by our modern way of 24-hour living and eating. The concept of when we eat may be just as important as what we eat for weight loss.

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Circadian rhythms are the 24 hours fluctuations that the majority of our cells, organs and tissues in our body are attuned to. This 24-hour clock that our body is set to is controlled by a variety of factors, these are termed time-givers or the more technical term used in the literature “zeitgebers”. The predominant and more well known time-giver is daylight, however food intake is also another powerful time-giver. The timing of meals consumed across the day has shown to have profound effects on insulin sensitivity. Chrono-nutrition refers to coordinating meal timings within our body’s daily 24 hour rhythms to optimise its response to an eating occasion.

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Our modern lifestyle is fast becoming 24 hours per day, now more than ever we have unlimited access to food. Recently the concept of reducing the duration of time we eat over a day has been explored with fascinating results. This approach is termed “Time restricted eating (TRE), where food is consumed ad libitum across an eating window that is defined from the first to the last eating occasion. For many of us a typical eating window may be between 12-14 hours, (7 am - 9 pm = 14-hour window). Research has focused on reducing this eating window to 8-10 hours with an emphasis on an earlier window to optimise circadian biology. This has clearly demonstrated greater insulin sensitivity earlier in the day with diminishing returns as the day turns into night. Consistent meal timing and the subsequent period of fasting (14-16 hours) is believed to prime nutrient pathways to optimise glycaemic control and promote the reduction in fat mass.

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In one of the pioneering studies to date done in humans, Panda & Gill asked overweight subjects to simply reduce their eating window to less than 10 hours as guided by a simple mobile phone application. Subjects were not asked to change the nutritional quality or quantity of what they ate. Subjects reported weight loss of ~3% body mass and this was maintained for 12 months. Also of interest by reducing this eating window to 10 hours subjects inherently reduced their total energy (calorie) intake by approximately 20%. This is an emerging area of research and for those interested to read in more breadth we have outlined some relevant reading below.

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Here at Axis, when working with an Osteoarthritis patient where weight loss is a priority, educating around the timing of their eating can be a vital tool in the toolbox for their nutrition program. Our core focus for weight loss in Osteoarthritis patients is creating long term, sustainable change in eating behaviours to reduce their daily energy intake. In many patients there is significant opportunity to reduce the eating window, often simply having a zero-tolerance approach to snacking after dinner reduces many of the high calorie / energy dense foods that we eat out of habit that significantly increases daily energy consumption. Also this is eaten at time where we highly inactive and often sedentary, which limits the role of activity and exercise in optimising our metabolic response to food.

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Below are some time restricted eating tips that are worth considering if weight loss is a priority for your osteoarthritis management.

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1. Aim to reduce your eating window to 10-12 hours, start by seeing if you can implement a 12-hour window if this seems unrealistic at first. This means if you finish dinner at 7 pm aim to avoid eating again until 7 am the following morning. As you become more familiar with this lifestyle, move breakfast slightly later towards 9 am. Remember breakfast is still a vital meal and our metabolic response is at its greatest mid-late morning.
2. Caffeine consumption is considered to break your fast, keep to water or non caffeinated herbal teas outside of your eating window.
3. Try to avoid late windows, the research tends to support “an earlier the better” approach but this needs to fit with your lifestyle for longer term success. Work towards an earlier dinner by 7-7.30pm at the latest.
4. Aim for this for 5 days out of 7. It's important to maintain reality and social acceptance such as eating out with friends / family.
5. Give it a go and see how you feel, the first few days can be an adjustment period but for many its an effective tool for weight loss. Research suggests hunger is not increased in those following time restricted eating strategies and that adjustment is easily achievable.

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Reading

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Hawley, J.A., Sassone-Corsi, P., Zierath, J.R. Chrono-nutrition for the prevention and treatment of obesity
and type 2 diabetes: from mice to men. (2020) Diabetologia Link

Parr, E.B., Heilbronn, L.k., Hawley, J.A. A Time to Eat and a Time to Exercise. (2020). Exercise and Sports Science Reviews. (2020). Link

Gill, S., Panda, S. A smartphone app reveals erratic diurnal eating patterns in humans that can be modulated for health benefits. (2015). Cell Metabolism Link

Podcasts

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We do Science #127: Time Restricted Eating and Exercise with Evelyn Parr (PHD).

Sigma Nutrition #271: Circadian Metabolomics & Time-Restricted Feeding. Professor John Hawley