Rediff.com  » Getahead » Not losing weight? Don't just blame calories

Not losing weight? Don't just blame calories

March 08, 2020 08:26 IST
Get Rediff News in your Inbox:

It's not just how many calories you eat, but when you eat them that will determine how well you burn those calories.

It's not just how many calories you eat, but when you eat them

Image published for representational purposes only. Photograph: Kind courtesy jarmoluk/Pixabay.com

While excessive attention is paid in determining what you eat, how much you eat, and how much exercise you get, an important factor of 'when' to consume is often neglected.

New research has identified that it's not just how many calories you eat, but when you eat them that will determine how well you burn those calories.

The research published in the journal PLOS Biology, conducted by Kevin Kelly, Owen McGuinness, Carl Johnson and colleagues of Vanderbilt University, USA suggests that your biological clock and sleep regulate how the food you eat is metabolized, thus the choice of burning fats or carbohydrates changes depending on the time of day or night.

Your body's circadian rhythm has programmed your body to burn fat when you sleep, so when you skip breakfast and then a snack at night you delay burning the fat.

Over two separate 56-hour long sessions, the researchers monitored the metabolism of mid-aged and older subjects in a whole-room respiratory chamber using a 'random crossover' experimental design.

In each session, lunch and dinner were presented at the same times (12:30 and 17:45, respectively), but the timing of the third meal differed between the two halves of the study.

Thus in one of the 56-hour bouts, the additional daily meal was presented as breakfast (8:00) whereas, in the other session, a nutritionally equivalent meal was presented to the same subjects as a late-evening snack (22:00). The duration of the overnight fast was the same for both sessions.

Whereas the two sessions did not differ in the amount or type of food eaten or in the subjects' activity levels, the daily timing of nutrient availability, coupled with clock/sleep control of metabolism, flipped a switch in the subjects' fat/carbohydrate preference such that the late-evening snack session resulted in less fat burned when compared to the breakfast session.

The timing of meals during the day/night cycle, therefore, affects the extent to which ingested food is used versus stored.

This study has important implications for eating habits, suggesting that a daily fast between the evening meal and breakfast will optimise weight management.

Get Rediff News in your Inbox:
SHARE THIS STORYCOMMENT