The new diet plan, called 'One You' campaign, was launched in a bid to tackle the 'calorie creep' that's causing around two thirds of adults in England to be overweight or obese.
But if you were expecting complicated guidelines on how to cut down your calorie intake, turns out the tip is quite simple - and catchy.
To keep tabs on how many calories you're consuming everyday, Public Health England are encouraging people to follow the 400-600-600 rule.
The new 400-600-600 plan aims to keep adults from consuming excess calories, which can lead to unhealthy weight gain
What is the 400-600-600 plan?The new diet means you should eat around 400 calories for breakfast, 600 for lunch and 600 for dinner, as well as a couple of healthier snacks and drinks in-between.
The tip, designed to provide a rule of thumb and not a weight loss programme, ensures adults keep to the recommended daily calorie intake - 2,000 for women and 2,500 for men each day.
To follow the plan, you could whip up meals that are 500 calories or less and have a dessert that's around 100 calories.
This baked sausage and fennel gnocchi gratin is 426 calories, which means you'd have 174 calories left for dessert or a drink, according to the 400-600-600 plan
Why was the 400-600-600 plan created?The extra calories adults are consuming everyday build up and can cause unhealthy weight gain - that can lead to health issues like heart disease, Type 2 diabetes and some cancers - which is why Public Health England have launched the 400-600-600 plan.
Dr Alison Tedstone, chief nutritionist at PHE, said: 'It's clear that excess calories are driving weight gain for many. Busy lives and too much food mean we're often eating more food than we realise – especially when we're grabbing food out and about. This can have a significant impact on our waistlines and our health.
'The 400-600-600 tip can help people make healthier choices when eating and drinking on the go. It's encouraging to see major high street companies promoting lower calorie options and we hope more will follow suit.'
How can you follow the 400-600-600 plan when eating out?One of the main factors leading to people eating more calories than they need is eating out, and to tackle the issue, Public Health England are working with a number of retailers to provide healthy options for customers.
Greggs, McDonalds, Starbucks and Subway are involved in the scheme, which will see 400 and 600 calorie meal options being signposted to customers through advertising, in-store promotion, social media and other online channels.
As well as observing the calorie limit, all recommended meals will also be below maximum recommendations for sugar, saturated fat, salt.
McDonalds have already launched their 'Meals Under' menu bundles earlier this year, which gives customers a range of meal options that are under 400 or 600 calories.
Will you be following the new 400-600-600 rule? Let us know in the comments!