Reading a nutrition label takes about 20 seconds. Use the per 100g column, glance at four numbers (sugars, saturated fat, sodium and fibre), then read the first three ingredients. That is the whole job. Mr PT Fitness is a private home studio in Dee Why run by Matt Reilly, a personal trainer with 10+ years' experience, and this is the version of label reading we teach clients who have no interest in becoming nutrition hobbyists. You are not auditing the packet. You are deciding between two products in an aisle in Dee Why with a trolley in the way.
What actually matters on a nutrition label?
Five lines do almost all the work: sugars, saturated fat, sodium, fibre and protein, all read in the per 100g column. The rest of the Nutrition Information Panel is detail you do not need to make a decision between two packets.
These are general guide numbers, not rules. A food can sit over the line on one row and still be a sensible thing to eat, which is why you read the whole row rather than hunting for a single villain.
| Line on the panel | Low (per 100g) | High (per 100g) | What it tells you |
|---|---|---|---|
| Sugars | Under 5g | Over 15g | How much of the product is sugar, natural and added combined |
| Saturated fat | Under 3g | Over 5g | The fat type worth keeping an eye on across a whole week |
| Sodium | Under 120mg | Over 400mg | Salt content, which adds up quickly across packaged foods |
| Fibre | Under 3g | Over 6g | How filling it is likely to be, and the quality of the carbohydrate |
| Protein | Under 5g | Over 10g | Whether the food can anchor a meal or is mostly carbohydrate and fat |
Energy in kilojoules sits at the top of every panel and matters underneath all of this, because total intake still decides whether body weight moves. The reason why is in energy balance explained. In an aisle, though, the five lines above are faster to act on than a kilojoule figure you cannot place in context.
Should I read the per 100g or the per serve column?
Read per 100g when you are comparing two products, and per serve when you want to know what you are actually about to eat. Per 100g is a fixed measure, so it is the only fair comparison between brands.
Serving sizes are chosen by the manufacturer and are not standardised between products. That is the trap. Two boxes of muesli sitting next to each other can use completely different serves, and the smaller serve flatters the worse product.
- Brand A: 30g serve, 9g of sugars per serve. That is 30g of sugars per 100g.
- Brand B: 50g serve, 11g of sugars per serve. That is 22g of sugars per 100g.
On the per serve column Brand B looks worse (11g against 9g). On the per 100g column Brand A is clearly the sugarier cereal. Same two boxes, opposite conclusion, and the only difference is which column you read.
Per serve still has a use. Once you have picked the product, the per serve column tells you what lands in the bowl, as long as you check the serve size is close to what you actually pour. For most cereals it is not.
Want a straight answer on your actual shopping list?
Free 15-minute consult at the Dee Why studio. Bring three products you are unsure about and we will go through the panels together. Book here or call 0422 745 334.
How do you read the ingredients list?
Ingredients are listed in descending order by weight, so the first three make up most of what is in the packet. If a form of sugar appears in the first three, it is a sugary product regardless of what the front of the pack says.
Sugar travels under a lot of names, and splitting it across several of them pushes each one further down the list. Worth recognising: cane sugar, glucose, glucose syrup, fructose, dextrose, maltose, maltodextrin, molasses, rice malt syrup, honey, agave, and fruit juice concentrate.
The list is also useful for the opposite reason. A short ingredients list of recognisable foods usually means the product is close to what it claims to be. Wholegrain oats, almonds and dried fruit is a different product from wholegrain oats, glucose syrup, vegetable oil and humectant, even when both boxes say muesli.
One more detail that saves time: Australian labels show the percentage of the characterising ingredient. A pie that says beef (12%) is telling you something the picture on the front is not.
What do sugar, fibre and protein tell you at a glance?
Sugar tells you how quickly the food is eaten, while fibre and protein tell you how long it keeps you full. That trio explains most of why one snack holds you to lunch and another leaves you back in the pantry at 11am.
The sugars line on an Australian panel combines naturally occurring and added sugars in one number. This is why plain milk reads around 5g per 100g and plain Greek yoghurt reads higher than people expect, from lactose rather than anything added. The ingredients list is what separates the two, so read the pair together rather than judging on the panel alone.
Fibre and protein are the two lines most people never look at, and they are the ones that change how a day of eating feels. A cereal with 10g of fibre per 100g and 12g of protein per 100g behaves differently from one with 2g and 5g, even when the kilojoules match. The same logic applied to meals is covered in protein at every meal, and it is part of what we set up in the 1-on-1 sessions from $50 listed under services.
What can you safely ignore on the label?
Ignore the front of the pack. Claims like natural, wholesome, no artificial colours and even high in protein are marketing decisions, not nutrition information. The panel on the back is regulated and consistent. The front is not.
- Low fat: a regulated term in Australia, meaning under 3g of fat per 100g for a food. It does not mean low in energy or low in sugar.
- No added sugar: accurate but limited. The product can still be high in total sugars from fruit juice concentrate or dried fruit.
- Health Star Rating: genuinely useful for comparing products within the same category, such as two breakfast cereals. Comparing a cereal to a yoghurt with it is not what it was built for.
- Serving suggestion imagery: the photo usually includes food that is not in the packet.
The point of all this is speed, not precision. Twenty seconds on the back of two packets beats twenty minutes reading about nutrition online, and it is a skill that gets faster every shop until you stop noticing you are doing it.
This is general nutrition guidance within the scope of a personal trainer. If you have a diagnosed condition, a food allergy or intolerance, are pregnant, or have a history of disordered eating, work with your GP or an Accredited Practising Dietitian rather than making changes on your own.
General information, not individual medical or dietary advice. See your GP or an Accredited Practising Dietitian (APD) for your situation.
Frequently asked questions
Should I look at per 100g or per serve?
Use per 100g to compare two products and per serve to work out what you are actually eating. Serving sizes are set by the manufacturer and vary between brands, so the per serve column can make a sugary product look better than a plainer one simply because the serve is smaller.
How much sugar is too much?
As a general guide, under 5g of sugars per 100g is low and over 15g per 100g is high for a packaged food. The sugars line combines natural and added sugars, so plain milk and yoghurt read higher than you might expect. Check the ingredients list to tell the two apart.
Are low fat labels a trick?
No, but low fat does not mean low energy. In Australia a food labelled low fat has under 3g of fat per 100g, and sugar or starch is sometimes added to replace the texture and flavour. Ignore the front of the pack and compare the per 100g panel on both products.
Stop guessing in the supermarket aisle
Free 15-minute consult at the Dee Why studio. We will sort the shopping list, set a protein target you can actually hit, and build training around it. Clients come from Dee Why, Brookvale, Curl Curl and Collaroy.