How to make your diet more sustainable, healthy or cheap – without giving up nutrients


People choose certain foods or change their diets for a variety of reasons: to improve their health, lose weight, save money, or because of concerns about sustainability or the way the food is produced.

Consider the trend towards low-fat products in the 1980s and low-carb diets in the 1990s, and now the rise of plant-based protein products and ready-to-eat meals.

But before you ditch your traditional food choices, it’s important to consider the nutritional trade-offs. If you replace one food with another, are you still getting the vitamins, minerals and other nutrients you need?

In a recent article, I sought to raise awareness of the nutritional differences between foods by producing a new index specific to Australia. It aims to help Australians make more informed food choices and get the nutrients recommended for good health.

Before abandoning your traditional food choices, it’s important to consider the nutritional trade-offs.

Nutrients: are we getting enough?

The Australian Bureau of Statistics publishes tables showing the usual intake of selected nutrients in the population. The tables also show the proportion of Australians whose usual nutrient intake is below what is known as the ‘estimated average requirement’.

While Australian adults eat in a variety of ways, they generally get enough of certain nutrients regardless of their diet.

For example, most people seem to get enough niacin (vitamin B3) and phosphorus. And the charts suggest that 97% of Australians are getting enough vitamin C.

However, insufficient intake of calcium, magnesium, vitamin B6 and zinc is common.

About two-thirds of Australian adults consume less calcium than is recommended (which varies from 840 to 1100 mg/day depending on age). Worryingly, 90% of women over 50 do not consume enough calcium.

Inadequate zinc intake is most common among Australian men – more than half of over-50s consume below recommended levels.

What about free sugars then? These include added sugars and the sugar component of honey and fruit juices, but exclude natural sugars found in fruits, vegetables and whole milk.

It is recommended that Australians limit free sugars to less than 10% of dietary energy intake. However, nearly 50% of Australian adults exceed this recommended limit.

Read more: Don’t drink milk? Here’s how to get enough calcium and other nutrients

older women painting at the table
Worryingly, 90% of women over 50 have a lower calcium intake than recommended.

Pay attention to under-consumed nutrients

Each food has a different nutritional composition. And as the Australian Dietary Guidelines show, we need to eat a variety of foods to stay healthy.

We need to pay particular attention to foods that are important sources of nutrients that many Australians do not get enough of. If possible, Australians should seek to include more of these foods in their diet.

At the same time, foods containing free sugars should only be eaten in moderation.

The new Food Index I have produced aims to help Australians achieve this goal. It provides an overall nutritional composition score tailored to the Australian dietary context.

The index includes eight vitamins (B1, B2, B3, B6, B12, folate, A and C), eight minerals (calcium, phosphorus, zinc, iron, magnesium, iodine, selenium and molybdenum), as well as proteins and free sugars.

These 18 items are weighted in proportion to the extent of insufficient or excessive intake in Australia. A high score is better than a lower score.

Thus, the index gives a high score to foods if they are low in free sugars and high in the elements that many Australians need most – calcium, magnesium, vitamin B6, zinc and vitamin A.

Foods with few nutrients but added sugars score very low. For example, a chocolate chip cookie weighing 35 grams scored 0.004 and a sweet cola flavored drink scored less than zero.

woman eats a chocolate bar
Foods with few nutrients but added sugars score very low on the index.
Matt Dunham/AP

Food exchange may not reach the same level

The index can be used to compare foods that might be considered substitutes in the pursuit of a healthier, more affordable, or better-for-the-environment diet.

In the case of dairy products, 250ml of whole milk scored 0.160 and low fat milk almost as much at 0.157.

The index shows the potential nutritional trade-offs when choosing dairy alternatives. A 250ml serving of calcium fortified oatmeal drink scored 0.093. Without calcium fortification, the score fell to 0.034.

When it comes to meat, 100g of diced lean raw beef scored 0.142. An equivalent serving of plant-based burger made with pea protein, with many added vitamins and minerals, scored nearly identically at 0.139. This shows that plant-based alternatives are not necessarily less nutrient dense.

The index also shows the different nutritional needs of women and men. For example, scores for two large eggs were higher for females (0.143) than for males (0.094). This reflects, in part, the greater prevalence of inadequate iron intake among young women.

Read more: How Australia can boost grain production while reducing its carbon footprint

Buyers browse the food market
The packaging of unprocessed foods generally does not include nutritional information.

Understand trade-offs

To date, complete nutritional information on foods consumed in Australia has only been found in databases used by scientists and nutrition professionals.

For the average consumer, packages of unprocessed foods, such as fruits and vegetables, fresh meats and some cheeses, generally do not contain nutritional information.

Consumers can check the nutrition information panel when shopping for processed foods, but only certain nutrients are listed.

I hope my research will inspire manufacturers to produce foods that are more nutrient dense or those formulated to meet the nutritional needs of a particular subgroup.

In the future, I hope the index will also be translated into a user-friendly format or app that everyday Australians can consult, to ensure that their changing food preferences translate into a healthier choice.

Read more: Meat and masculinity: why some men just can’t stand plant foods


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