Calories, Clocks & Causality

Calories, Clocks & Causality

Posted on behalf of Harriet Fender

The simple ‘calorie’ is a unit of energy (equivalent to 4.2 joules) and is relevant to the fine balance that exists between our diet and our metabolic requirements (i.e. energy intake versus energy expenditure). A caloric deficit can deplete the body’s energy reserves and may impair physiological function (e.g. fatigue); a caloric surplus can expand the body’s energy reserves and may impair long-term health (e.g. obesity).


Humans have therefore evolved highly sophisticated feedback mechanisms to regulate the availability of metabolic fuels and maintain energy balance. This is a remarkable feat given that over one-billion calories typically enter and exit our bodily system each year, so there are understandably instances when energy imbalances can occur and modern science may present opportunities to help either replenish energy stores following acute depletion (e.g. post-exercise recovery) or to reduce energy stores following chronic accumulation (e.g. weight loss). Unfortunately, nutrition research in general suffers from two key limitations that often render current dietary guidelines incomplete and inaccurate.


Regarding completeness, almost everything we know about nutrition is based on how much we eat and what we eat (i.e. quantity and type), yet we are only recently realising the importance of when we eat (i.e. time; chrononutrition). Regarding accuracy, too often dietary guidelines simply recommend emulating the eating habits of people who tend to be more healthy, yet diet is just one of many reasons why some people may be more healthy than others (i.e. correlation does not infer causality).


To provide reliable evidence-based recommendations we need to determine whether specific lifestyle changes actually cause any meaningful effects on health, which can be achieved using randomised controlled trials. Such experimental designs have recently been applied to advance our understanding of time in relation to nutrition, from a molecular level through to whole-body physiology.


This lecture will summarise this new evidence by drawing from a wide range of human research trials that have tested common but often extreme experimental models, including: intermittent fasting (e.g. extended morning/evening or alternate-day), time-restricted feeding, continuous feeding, nocturnal feeding, maximal eating occasions and the general scheduling of daily nutrient ingestion relative to time-of-day, usual meal times, sleep and physical exercise. The available evidence will inform overall conclusions that reflect the state of current understanding regarding meal timing and circadian rhythms in relation to bodily energy stores, metabolic health and physiological function.


This lecture is part of the Faculty of Humanities and Social Sciences inaugural lecture series for 2018-19 and will be introduced by Professor Ian White, Vice-Chancellor and President at the University of Bath.


The lecture will be followed by a drinks reception in The Edge Foyer. Please contact Harriet Fender with any dietary requirements.

22 May 2019 at 6:05pm
until 22 May 2019 at 7:05pm
The Edge Lecture Theatre
University of Bath

Share this story

This story was shared by

Bath Info logo

Bath Info

Bringing you information about interesting community events in and around the Bath area.
Find out more about Bath Info

Join our mailing list

Email updates

Cancel Join now

A member of


A community brought to you by BANES 3rd Sector Group