WHEN it comes to losing weight there must be a thousand different theories out there.

Eat more protein, intermittently fast, cut out carbs, eat little and often…the list goes on.

Getty – Contributor Eating most of your calories at lunch time could be the key to losing weight

But what if it was a simple as when you eat your food, instead of what you can and can’t eat?

The time we eat has a big impact on our internal body clock, which can have a huge impact on our waistlines.

You may think your body clock, also known as the circadian rhythm, only affects your sleeping patterns, but the fact is there a clock in every cell of your body.

And eating a big meal late at night is not the right thing for your metabolism – instead you should be having a big lunch.

Getty – Contributor When we eat can have a hug impact on our body’s internal clock

Nutritionist Helen Bond told The Sun Online: “There is evidence coming through that having the majority of your calories earlier in the day seems to be more beneficial than having a heavier evening meal.

“It’s about shifting the bulk of your calorie intake more to the middle part of the day rather than eating a big meal late at night and going to bed on an empty stomach.

“But it’s also important to be mindful of your overall calorie intake throughout the day.

“There is no point in having a very calorific meal at lunchtime and not compensating by eating less later on.

Getty – Contributor When we eat a big lunch our body is able to burn the calories better over the afternoon

“If you have a more carbohydrate calories based meal at lunchtime then you are going to be burning those calories more efficiently in terms of insulin levels and your metabolism.”

But it’s important not to forget about eating well for breakfast and dinner, Helen said.

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“The old tradition is breakfast like a king, lunch like a prince and dinner like a pauper, and I think that very much rings true today,” she added.

“Having a good breakfast refuels you after the overnight fast and provides you with energy to concentrate and improves your mood.

“For lunch time if you are having a heavier meal you have the afternoon to use all those calories.

Getty – Contributor It’s still important to make sure you are eating the right calories – a burger and fries is not a healthy option for lunch

“It means you are going to bed with not such a heavy stomach and your body can metabolise those calories more efficiently.

“Calories in calories out still has a bearing on how much weight gain or maintain, but also what is really important is the nutrient density of those calories.

“Not all calories are equal and if your diet is lacking in nutrition that’s not going to be beneficial for your weight as well.”

Some evidence suggests you use more energy to burn off a meal earlier in the day than you do at night.

And animal studies have found that eating at specific times can help re-set the body’s circadian rhythm.

Other research has suggested a big breakfast can help you lose weight and treat diabetes.