A guide to cereal portions

Emma White - Nutritionist | 04 Sep, 2023

When someone new starts to use Nutracheck and asks for advice, one of the first tips we give is to make sure you weigh everything you eat – initially at least. Weighing food is the only way to accurately track portion sizes and get a clear idea of how many calories you're consuming.

It's all too easy to underestimate what a typical portion is if you rely on guessing, so weighing from the get-go helps by giving you a visual reference of what a 'portion' looks like.

What's the big deal about cereal?

If you're keeping a food diary to help you stay within a set calorie allowance, then accurate recording is essential. There are certain foods that people regularly overestimate the portion size of, and top of the list is...cereal! Any foods we just pour from a pack are easy to get wrong. In fact, we carried out a little experiment with our team in the office to see just how likely people are to overserve themselves cereal.

We asked everyone to pour themselves a 40g portion of three popular breakfast cereals. The results were fascinating – pretty much everyone served themselves way too much!

  • Muesli – 91% of people overestimated
  • Sultana Bran – 65% overestimated
  • Cheerios – 33% overestimated

The issue here is to do with accurate diary tracking. If you're pouring yourself what you believe to be a 'portion', and then choosing one of our pre-set serving options when you add it to your diary – you could be underestimating how many calories you've eaten. And while an under-report of 50 calories a day might sound insignificant – over days and weeks, it adds up.

The recommended serving size a lot of cereal manufacturers state on the pack is 30-45g, which sadly looks like a very meagre portion! And as our findings above show, people tend to pour themselves what looks like a reasonable amount, which is actually a fair bit more. So the point here is to weigh exactly what's in your bowl, so you can accurately track the amount you've eaten and avoid under-reporting.

Do I need to stick to a 30-45g portion?

This is a good question! While the suggested portion size for UK cereals is 30-45g, this combined with 125-150ml of semi-skimmed milk equates to around 230 calories. Even for someone following a calorie deficit for weight loss, this isn't really an adequate number of calories for a breakfast. For someone on a 1,400 calorie diet, we recommend the following breakdown as a guide:

  • Breakfast – 300-350 calories
  • Lunch – 400-450 calories
  • Dinner – 450-500 calories
  • Snacks – 150-200 calories

When it comes to cereal, the usual addition is milk, but adding other foods such as a yogurt or fresh or dried fruit will help to up the calorie and nutrient profile of your breakfast. If your cereal of choice is one of the higher sugar options such as Cheerios or Crunchy Nut Cornflakes which aren't as rich in important nutrients such as fibre, then topping up your meal in this way with a low-fat yogurt and a piece of fruit is the way to go.

If, however, you're opting for porridge oats, Shredded Wheat, Weetabix, no-added-sugar muesli, or Bran Flakes – simply having a bigger serving of these cereals is not a problem. These lower sugar cereals are a great source of fibre, some are fortified with vitamins and minerals, and when teamed with a low-fat milk of your choice, they provide a good source of protein and fibre to start your day. Top with an 80g portion of mixed berries for a 5-a-day serving too and you're onto a winner. For these type of cereals a 50-60g breakfast portion is absolutely fine!

Take home message

When we talk about weighing cereals, it's not necessarily about an absolute requirement to stick to the 'recommended' 30-45g, it's more about understanding what a typical portion looks like to ensure you are accurately tracking your calories. Pouring out what looks like an adequate bowl full is probably going to be closer to double the recommended serving size, so make sure you weigh your portion and don't just assume it's 30g!

Nutritionist Emma White (ANutr), MSc Human Nutrition is passionate about how food science applies to the human body, and how the nutrients in what we eat affect us and ultimately have an impact on our health.

This site uses cookies to personalise content and ads, provide social media features and analyse our traffic. Find out more about how we use cookies.

Choose which cookies you allow us to use. You can read more about our Cookie Policy in our Privacy Policy.