Life Wellbeing Dieters should set a calorie limit per meal, not per day, study says

Dieters should set a calorie limit per meal, not per day, study says

Calorie counters may want to rethink their methods. Photo: Getty
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Setting a calorie limit per meal rather than per day can help dieters lose weight, research suggests.

A new study found that dieters who were asked to work out a calorie limit per meal were more likely to eat less than those who came up with a plan of how many calories they may eat over the course of a day.

Experts at Warwick Business School showed two groups of 50 people pictures of food with a suggestion of how many calories were on each plate.

Participants were also given an idea of daily calorie consumption by gender and age and asked to work out their own budget.

The results, published in the Journal of Consumer Research, showed those dieters who worked out a calorie allowance per meal and per snack set an overall average budget of 1528 calories.

The second group, who just thought about what they may eat overall, set an average budget of 2011 calories per day.

The benefits of calorie counting

When it came to what they actually ate, thinking about the calorie content per meal had a beneficial effect.

Slimmers who budgeted for each meal separately actually consumed an average of 1417 calories, 219 fewer than those with a single daily limit.

Dr Miaolei Jia, associate professor at Warwick Business School, who led the study, said those with a daily budget thought about cutting calories for meals such as dinner and snacks, where they thought they were most likely to over-consume, but did not think about other meals.

“Those who budgeted on a meal-by-meal approach cut the calories in all the meals they ate, which drove down their daily allowance,” Associate Professor Jia said.

Aradhna Krishna, from the University of Michigan, who also worked on the study, said the approach may also work for those wishing to reduce smoking or drinking.

Meal-timing strategies

Meal-timing strategies such as intermittent fasting have gained popularity over the past few years, and research suggests that such methods can lead to weight loss.

A recent study found that meal-timing primarily works by lowering appetite, which in turn may lead to more fat being burnt, on average, over a 24-hour period.

The study is the first to show how meal-timing affects 24-hour energy metabolism when food intake and meal frequency are matched.

But hang on? Timing your meals won’t burn more calories – but overall burns more fat? Aren’t they the same thing?

Well, no. Fat and calories aren’t the same thing. Calories are a unit of energy, which can come from carbohydrates, protein or fat.

When you’re working your body hard, calories are mainly burnt from carbohydrates stored in your muscles. When you’re awake and ordinarily active in a fasted state, the calories are burnt from stored fat.

The researchers found that early time-restricted feeding – a form of daily intermittent fasting where dinner is eaten in the afternoon – helped to improve people’s ability to switch between burning carbohydrates for energy to burning fat for energy, an aspect of metabolism known as metabolic flexibility.

The best time of day to burn calories

There’s a long-held belief that weight is controlled by a person’s genetics, diet and exercise habits, but last year, US scientists discovered that the number of calories or kilojoules people burn while at rest changes with the time of day.

When at rest, study participants burned 10 per cent more calories in the late afternoon and early evening than in the early-morning hours – a finding that suggests energy burn is dictated not only by what we eat, but also when we eat and sleep.

“There is now emerging evidence that an irregular sleep-wake and fasting-feeding cycle … can lead to disrupted circadian timing, which in turn may alter energy balance and lead to increased obesity risk,” the study authors wrote.

-with AAP 

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