That mouthful of chips comes with a bad payload.

The taste and sound explosion of a mouthful of chips comes with an undesirable payload.

Question: Your September 17 column suggested opting for popcorn over potato chips. But are corn chips a healthier option than potato chips? Or is any benefit of corn chips lost in the processing?

It’s all in the crunch. Yet a survey of the array of chips in the snack-food aisle of any supermarket can give the impression that flavour is the key to their success. You’ll see honey soy chicken, salt and vinegar, sea salt, sweet chilli and numerous others. But according to food technologists, the crunchiness of foods such as potato chips is a large part of what makes them so appetising. Unfortunately, crunch comes at a nutritional cost.

Corn and potato are both naturally low in fat. However, the chip-manufacturing process involves frying the raw ingredients to make them crunchy. In the process, the fat – and thus energy – content of the products is dramatically increased. However, one of these chips does have an edge on the other when it comes to fat.

An average corn chip contains about 2010kJ of energy per 100g, slightly less than the average 2170kJ per 100g of potato chips. However, the corn chip has notably less fat, averaging about

23.3g per 100g, compared with the average potato chip’s 36.8g per 100g. In other words, potato chips contain about 60% more fat than corn chips, and a significant proportion of that is the undesirable saturated fat linked to high blood cholesterol.

Corn chips tend to have a slightly higher carbohydrate content and more fibre. They contain 6.6g of fibre per 100g compared with 3.8g for potato chips.

Both these snack options fall well short of the nutritional prestige of popcorn. Popcorn is a whole grain with an intact kernel full of fibre – about 14.5g per 100g. That’s nearly four times what you’ll find in a potato chip and more than double the fibre of corn chips.

Popcorn also contains significantly less sodium and fat, so at 1330kJ per 100g, its energy per serving is much lower than corn or potato chips. Popcorn also has natural antioxidants.

As to the whether corn chips trump potato chips, it’s true to say that corn chips are not quite as unhealthy as potato chips. But their energy and sodium content are high and they offer little in the way of useful nutrients. They’re best eaten occasionally.

Popcorn, however, is a healthy snack that can be enjoyed every day, along with nuts, fruits and vegetables.

In the manufacturing process, the fat content of the products is dramatically increased.

Question: I bought some standard milk and noticed on the label it had 4.7g of sugar per 100g. Is this added sugar or does it occur naturally in milk?

The sugar listed on the nutrition information panel for standard cows’ milk is lactose, a sugar that occurs naturally in milk. Lactose is a unit of glucose and a unit of galactose bonded together. Lactase, an enzyme in our gastrointestinal system, breaks the bond so we can absorb the glucose and galactose separately.

There is no evidence of any harm from consuming milk sugars or the sugars found in fruit and vegetables, says the World Health Organisation (WHO). So milk sugars are not in the undesirable

sugars category that the WHO refers to as “free sugars”.

The undesirable free sugars that we should limit to less than 10% – or ideally 5% – of our total energy intake include those in honey, syrups (such as maple syrup and rice malt syrup),

There is no evidence of any harm from consuming milk sugars.

fruit juices and fruit-juice concentrates. Sugars added to foods or drinks by manufacturers or cooks – sucrose and fructose, for example – are also on the undesirable list.