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

Building a Strong Online Presence with Katoomba Web Design

Katoomba web design is more than just creating a website that looks good—it’s about building an online presence that reflects your brand, engages your audience, and drives results. For local businesses in the Blue Mountains, a well-designed website a...

September Sunset Polo

International Polo Tour To Bridge Historic Sport, Life-Changing Philanthropy, and Breath-Taking Beauty On Saturday, September 6th, history will be made as the International Polo Tour (IPT), a sports leader headquartered here in South Florida...

5 Ways Microsoft Fabric Simplifies Your Data Analytics Workflow

In today's data-driven world, businesses are constantly seeking ways to streamline their data analytics processes. The sheer volume and complexity of data can be overwhelming, often leading to bottlenecks and inefficiencies. Enter the innovative da...

7 Questions to Ask Before You Sign IT Support Companies in Sydney

Choosing an IT partner can feel like buying an insurance policy you hope you never need. The right choice keeps your team productive, your data safe, and your budget predictable. The wrong choice shows up as slow tickets, surprise bills, and risky sh...

Choosing the Right Legal Aid Lawyer in Sutherland Shire: Key Considerations

Legal aid services play an essential role in ensuring access to justice for all. For people in the Sutherland Shire who may not have the financial means to pay for private legal assistance, legal aid ensures that everyone has access to representa...

Watercolor vs. Oil vs. Digital: Which Medium Fits Your Pet's Personality?

When it comes to immortalizing your pet’s unique personality in art, choosing the right medium is essential. Each artistic medium, whether watercolor, oil, or digital, has distinct qualities that can bring out the spirit of your furry friend in dif...

The Times Features

NSW has a new fashion sector strategy – but a sustainable industry needs a federally legislated response

The New South Wales government recently announced the launch of the NSW Fashion Sector Strategy, 2025–28[1]. The strategy, developed in partnership with the Australian Fashion ...

From Garden to Gift: Why Roses Make the Perfect Present

Think back to the last time you gave or received flowers. Chances are, roses were part of the bunch, or maybe they were the whole bunch.   Roses tend to leave an impression. Even ...

Do I have insomnia? 5 reasons why you might not

Even a single night of sleep trouble can feel distressing and lonely. You toss and turn, stare at the ceiling, and wonder how you’ll cope tomorrow. No wonder many people star...

Wedding Photography Trends You Need to Know (Before You Regret Your Album)

Your wedding album should be a timeless keepsake, not something you cringe at years later. Trends may come and go, but choosing the right wedding photography approach ensures your ...

Can you say no to your doctor using an AI scribe?

Doctors’ offices were once private. But increasingly, artificial intelligence (AI) scribes (also known as digital scribes) are listening in. These tools can record and trans...

There’s a new vaccine for pneumococcal disease in Australia. Here’s what to know

The Australian government announced last week there’s a new vaccine[1] for pneumococcal disease on the National Immunisation Program for all children. This vaccine replaces pr...