The Times Australia
The Times World News

.

Does it matter what time of day I eat? And can intermittent fasting improve my health? Here's what the science says

  • Written by Frederic Gachon, Associate Professor, Physiology of Circadian Rhythms, Institute for Molecular Bioscience, The University of Queensland
Does it matter what time of day I eat? And can intermittent fasting improve my health? Here's what the science says

Early hunter-gatherers faced long periods of fasting. Their access to food[1] relied on successful hunting, fishing, and the availability of wild plants.

Over time, the development of modern agriculture and the transition to industrialised societies changed our regular eating patterns[2], shifting our dinner time to later in the day to accommodate work schedules.

Today, with access to an abundance of food, we rarely experience prolonged periods of fasting, except for weight loss or religious practices. It’s now common[3] to have four or more meals a day, with the most calories consumed later in the day. Frequent snacking is also common, over a window of around 15 hours.

However, research increasingly shows our health is not only affected by what and how much we eat, but also when we eat. So what does this mean for meal scheduling? And can intermittent fasting help?

Our body clock controls more than our sleep

Our internal biological timekeeper, or circadian clock, regulates many aspects of our physiology and behaviour. It tells us to be awake and active during the day, and rest and sleep[4] during the night. It can also tell us the best time to eat.

Our body is biologically prepared to have food during the day. Food digestion, nutrient uptake and energy metabolism is optimised to occur when we’re supposed to be active and eating.

Man eats noodles at his desk
Eating when we’re supposed to be sleeping can impact our health. Shutterstock[5]

Working against this default stage, by regularly eating when we’re supposed to sleep and fast, can compromise these processes and impact our health. Erratic eating patterns[6], including late-night meals, have been linked to weight gain[7] and a greater risk of metabolic disease.

Shift-workers, for example, and people who work evening, night or rotating shifts, have a higher risk[8] of obesity, heart disease and diabetes.

But adopting an eating pattern that aligns with our circadian rhythm can reduce these risks.

Read more: Why does night shift increase the risk of cancer, diabetes and heart disease? Here's what we know so far[9]

So can intermittent fasting help?

Nutritional interventions are increasingly focused not only on “what” we eat but also “when”. Intermittent fasting is one way to restrict the timing, rather than the content, of what we eat.

There are several types[10] of intermittent fasting, one of which is time-restricted eating. This means eating all our calories in a consistent 8-12 hour, or even shorter, interval each day.

But is it backed by evidence?

Most of what we know today about intermittent fasting and time-restricted eating is from mouse studies[11], which demonstrate remarkable weight loss and overall health benefits associated with these types of dietary interventions.

However, some aspects of mouse physiology can be different to humans. Mice need to eat more frequently than humans and even a short period of fasting has a more significant physiological impact on mice. One day of fasting in mice leads to a 10% loss of body weight[12], whereas humans would need to fast for 14 days to achieve similar results[13]. This makes a direct translation from mice to humans more complicated.

While health benefits of intermittent fasting[14] and time-restricted eating[15] have also been observed in humans, the findings in respect of weight loss are less clear. Current data suggest only modest, if any, weight loss in human participants who undergo these diet regimens when compared to calorie-restricted diets.

Drawing definitive conclusions[16] in humans may be more difficult[17] because of the small sample sizes and individual differences in metabolism, variations in study design (such as the use of different protocols with varying times and duration of food restriction), and participants not complying with their instructions.

Man cooks meal
Results from mice studies might not translate directly to humans. Shutterstock[18]

Health benefits could be due to eating fewer calories

Most studies describing the health benefits of time restricted eating[19] or intermittent fasting[20] also found these diets were accompanied by calorie restriction: reducing the time of food access implicitly leads people to eat less.

Studies that controlled calorie intake did not detect any more benefits of intermittent fasting than calorie restriction[21] alone.

Read more: Restricting calories leads to weight loss, not necessarily the window of time you eat them in[22]

The weight loss and health benefits observed with intermittent fasting is likely attributed due to the resultant reduction in calorie intake[23]. Similar findings[24] have been reported for time-restricted eating.

Benefit of following our body clock

Nevertheless, time-restricted eating offers additional health benefits in humans, such as improved glucose metabolism and blood pressure, even without differences in calorie intake, in particular when restricted to the earlier part of the day[25] (that is, when having a six-hour eating window with dinner before 3pm).

Restricting food intake to the daytime for shift-workers can alleviate[26] metabolic differences caused by shift-work, whereas this effect is not observed when food intake is restricted to nighttime[27].

One idea is that consuming food early, in alignment with our circadian rhythm, helps to synchronise our circadian clock[28]. This restores the rhythm of our autonomous nervous system, which regulates essential functions such as breathing and heart rate, to keep our physiology “tuned”, as it was shown in mice[29].

While there’s much still to learn from research in this field, the evidence suggests that to maintain a healthy weight and overall wellbeing, aim for regular, nutritious meals during the day, while avoiding late-night eating and frequent snacking.

Read more: Yes, intermittent fasting can boost your health, but how and when to restrict food consumption is crucial[30]

References

  1. ^ access to food (pubmed.ncbi.nlm.nih.gov)
  2. ^ changed our regular eating patterns (pubmed.ncbi.nlm.nih.gov)
  3. ^ now common (pubmed.ncbi.nlm.nih.gov)
  4. ^ rest and sleep (theconversation.com)
  5. ^ Shutterstock (www.shutterstock.com)
  6. ^ Erratic eating patterns (pubmed.ncbi.nlm.nih.gov)
  7. ^ weight gain (pubmed.ncbi.nlm.nih.gov)
  8. ^ higher risk (theconversation.com)
  9. ^ Why does night shift increase the risk of cancer, diabetes and heart disease? Here's what we know so far (theconversation.com)
  10. ^ several types (pubmed.ncbi.nlm.nih.gov)
  11. ^ mouse studies (pubmed.ncbi.nlm.nih.gov)
  12. ^ loss of body weight (www.sciencedirect.com)
  13. ^ similar results (pubmed.ncbi.nlm.nih.gov)
  14. ^ intermittent fasting (jamanetwork.com)
  15. ^ time-restricted eating (www.nejm.org)
  16. ^ definitive conclusions (pubmed.ncbi.nlm.nih.gov)
  17. ^ difficult (pubmed.ncbi.nlm.nih.gov)
  18. ^ Shutterstock (www.shutterstock.com)
  19. ^ time restricted eating (pubmed.ncbi.nlm.nih.gov)
  20. ^ intermittent fasting (pubmed.ncbi.nlm.nih.gov)
  21. ^ calorie restriction (jamanetwork.com)
  22. ^ Restricting calories leads to weight loss, not necessarily the window of time you eat them in (theconversation.com)
  23. ^ calorie intake (pubmed.ncbi.nlm.nih.gov)
  24. ^ Similar findings (pubmed.ncbi.nlm.nih.gov)
  25. ^ earlier part of the day (pubmed.ncbi.nlm.nih.gov)
  26. ^ can alleviate (pubmed.ncbi.nlm.nih.gov)
  27. ^ nighttime (www.science.org)
  28. ^ synchronise our circadian clock (pubmed.ncbi.nlm.nih.gov)
  29. ^ in mice (www.pnas.org)
  30. ^ Yes, intermittent fasting can boost your health, but how and when to restrict food consumption is crucial (theconversation.com)

Read more https://theconversation.com/does-it-matter-what-time-of-day-i-eat-and-can-intermittent-fasting-improve-my-health-heres-what-the-science-says-203762

Times Magazine

Headless CMS in Digital Twins and 3D Product Experiences

Image by freepik As the metaverse becomes more advanced and accessible, it's clear that multiple sectors will use digital twins and 3D product experiences to visualize, connect, and streamline efforts better. A digital twin is a virtual replica of ...

The Decline of Hyper-Casual: How Mid-Core Mobile Games Took Over in 2025

In recent years, the mobile gaming landscape has undergone a significant transformation, with mid-core mobile games emerging as the dominant force in app stores by 2025. This shift is underpinned by changing user habits and evolving monetization tr...

Understanding ITIL 4 and PRINCE2 Project Management Synergy

Key Highlights ITIL 4 focuses on IT service management, emphasising continual improvement and value creation through modern digital transformation approaches. PRINCE2 project management supports systematic planning and execution of projects wit...

What AI Adoption Means for the Future of Workplace Risk Management

Image by freepik As industrial operations become more complex and fast-paced, the risks faced by workers and employers alike continue to grow. Traditional safety models—reliant on manual oversight, reactive investigations, and standardised checklist...

From Beach Bops to Alpine Anthems: Your Sonos Survival Guide for a Long Weekend Escape

Alright, fellow adventurers and relaxation enthusiasts! So, you've packed your bags, charged your devices, and mentally prepared for that glorious King's Birthday long weekend. But hold on, are you really ready? Because a true long weekend warrior kn...

Effective Commercial Pest Control Solutions for a Safer Workplace

Keeping a workplace clean, safe, and free from pests is essential for maintaining productivity, protecting employee health, and upholding a company's reputation. Pests pose health risks, can cause structural damage, and can lead to serious legal an...

The Times Features

The Role of Your GP in Creating a Chronic Disease Management Plan That Works

Living with a long-term condition, whether that is diabetes, asthma, arthritis or heart disease, means making hundreds of small decisions every day. You plan your diet against m...

Troubleshooting Flickering Lights: A Comprehensive Guide for Homeowners

Image by rawpixel.com on Freepik Effectively addressing flickering lights in your home is more than just a matter of convenience; it's a pivotal aspect of both home safety and en...

My shins hurt after running. Could it be shin splints?

If you’ve started running for the first time, started again after a break, or your workout is more intense, you might have felt it. A dull, nagging ache down your shins after...

Metal Roof Replacement Cost Per Square Metre in 2025: A Comprehensive Guide for Australian Homeowners

In recent years, the trend of installing metal roofs has surged across Australia. With their reputation for being both robust and visually appealing, it's easy to understand thei...

Why You’re Always Adjusting Your Bra — and What to Do Instead

Image by freepik It starts with a gentle tug, then a subtle shift, and before you know it, you're adjusting your bra again — in the middle of work, at dinner, even on the couch. I...

How to Tell If Your Eyes Are Working Harder Than They Should Be

Image by freepik Most of us take our vision for granted—until it starts to let us down. Whether it's squinting at your phone, rubbing your eyes at the end of the day, or feeling ...