Three weight-loss methods compared: eating earlier, fewer meals and intermittent fasting

Around the world, about one in eight people live with obesity. Carrying excess body fat matters because it raises the likelihood of type 2 diabetes, cardiovascular disease and some cancers.

Adjusting what you eat plays a key part in treating obesity and reducing the chance of further weight gain. That can involve cutting overall energy (calorie) intake, changing when you eat, and putting nutritious foods first.

But do certain approaches make weight loss more achievable than others? In new research, we compared three methods to find out whether any one strategy produced more weight loss than the rest:

• changing calorie distribution - eating a greater share of your daily calories earlier rather than later
• eating fewer meals
• intermittent fasting

To do this, we combined evidence from 29 clinical trials, covering nearly 2,500 participants.

Across studies lasting 12 weeks or longer, the average weight loss was broadly the same for all three approaches: 1.4–1.8 kg.

So if you are aiming to lose weight, it makes sense to pick the option - or mix of options - that best fits your routine and preferences.

Eating earlier in the day

When metabolism is not working as it should, the body may not respond effectively to insulin. Over time, this can contribute to weight gain and tiredness, and it can increase the risk of long-term conditions such as diabetes.

Eating later - for example, having a large evening meal followed by late-night snacking - appears to be linked with poorer metabolic function. In practical terms, the body may become less efficient at turning food into energy, keeping blood glucose steady and controlling fat storage.

By contrast, shifting calorie intake earlier in the day seems to support better metabolic function.

That said, the benefits may not be universal. Some people naturally have an evening "chronotype", meaning they tend to wake later and go to bed later.

People with this chronotype seem to find weight loss harder regardless of which approach they use. A mix of influences may be involved, including genetics, a greater tendency towards an overall poorer-quality diet, and higher levels of hormones that drive hunger.

Eating fewer meals

Many people skip breakfast - but does that make weight loss more difficult? Or is it preferable to have a larger breakfast and a lighter evening meal?

Although eating more frequently has been linked in some research to lower disease risk, recent studies have suggested that, compared with eating one or two meals a day, eating six times a day might be associated with greater weight loss success.

However, the wider body of evidence does not consistently support that idea, and it more often indicates that fewer meals can help with greater weight loss. Our findings point to three meals a day being more effective than six. A straightforward way to move towards this pattern is to drop snacks while keeping breakfast, lunch and dinner.

Most of the available research directly compares three meals with six meals, and there is relatively little evidence on whether two meals a day is better than three.

Even so, "front-loading" calories - taking in most of your daily calories between breakfast and lunch - appears to support weight loss and may also reduce hunger throughout the day. More long-term studies are needed to be confident about this.

Fasting, or time-restricted eating

Many of us spread eating across more than 14 hours each day.

Late-night eating can disrupt the body’s internal clock and change how organs work. Over time, this may raise the risk of type 2 diabetes and other chronic conditions, especially for shift workers.

Time-restricted eating is one form of intermittent fasting. It involves consuming all daily calories within a six- to ten-hour window during the day, typically when you are most active. The focus is not on changing what you eat or how much you eat, but on when you eat.

Animal research indicates time-restricted eating can support weight loss and improve metabolism. In humans, though, the evidence base remains limited - particularly regarding long-term effects.

It is also uncertain whether any benefits come from the timing itself or simply because people end up eating less overall. In studies where participants could eat as they wished (without deliberate calorie restriction) but followed an eight-hour daily eating window, they naturally ate around 200 fewer calories per day.

What will work for you?

Historically, clinicians have often treated weight loss and weight-gain prevention as a simple equation of calories consumed versus calories burned. But factors such as when calories are eaten during the day, how many times we eat, and whether we eat late at night may also shape metabolism, body weight and health.

There is no quick fix for losing weight. Instead, consider choosing an approach - or combining approaches - that you can realistically maintain. You could think about:

• trying to eat within an eight-hour window
• shifting calories earlier by putting more emphasis on breakfast and lunch
• sticking to three meals a day rather than six

On average, adults gain 0.4 to 0.7 kg each year. Improving overall diet quality is important for preventing this gradual weight gain, and the strategies above may help as well.

Finally, there is still much we do not know about these eating patterns. Many studies so far are short-term, include small numbers of participants and use different methods, which makes direct comparison difficult.

Further research is in progress, including tightly controlled trials with larger samples, more diverse groups of people and more consistent study designs. With time, this should help clarify how changing eating patterns may lead to better health.

Hayley O'Neill, Assistant Professor, Faculty of Health Sciences and Medicine, Bond University and Loai Albarqouni, Assistant Professor | NHMRC Emerging Leadership Fellow, Bond University

This article is republished from The Conversation under a Creative Commons licence. Read the original article.