For decades, we’ve been warned about foods high in cholesterol and saturated fats. But lately, attention has shifted to sugar: soft drinks, fruit juices and, surprisingly, yogurt have become the new “danger” foods. To get a better sense of what we should – and shouldn’t – eat when it comes to the sweet stuff, U of T Magazine editor Scott Anderson spoke with Prof. Mary L’Abbé, chair of the department of nutritional sciences.
Sugar seems to have replaced fat as the new dietary no-no. What’s wrong with sugar?
There’s nothing “wrong” with sugar in the sense of how our bodies metabolize it. We need a certain amount of sugar for energy; our brain needs sugar to function. The problem with sugar is the amount we consume. Excess sugar gets stored as fat.
The World Health Organization has recommended that no more than 10 per cent of our calories come from sugar. Is this guideline enough to address the issue?
I was on the panel that made this recommendation. It’s a start. One of the things we wanted to make clear is that the sugar you consume is not just the sugar you tip from a spoon into your coffee. Many beverages have sugars added in processing. Foods that you wouldn’t necessarily think of as sweet – with labels that say “no added sugar” – in fact have added fruit juices or fruit puree and are high in sugar. Yogurt is a good example of this.
How can individuals find out how much sugar they eat?
No one expects an individual to add up exactly how much sugar they’re getting in a day. But they should make themselves aware of the main sources of added sugar in their diet, such as juices, sport drinks and sodas. And they should acquaint themselves with recommendations for healthy eating, such as minimizing processed foods and eating more whole fruits and vegetables and whole grain products.
What’s the problem with processed foods?
Think of an apple. You can eat a whole apple or consume the same amount of “apple calories” in the form of apple juice. The sugar in the whole apple results in a slow increase in our sugar levels. But apple juice causes a sudden spike in our sugar levels, putting a strain on our insulin system. From a metabolic point of view, it’s much easier for our body to process the sugar when it’s in the form of an apple rather than apple juice. Over time, frequent and sudden spikes in our sugar level can lead to insulin resistance, Type 2 diabetes or metabolic syndrome.
How is this related to body fat?
When you experience a big spike in sugar levels, the sugar is pushed into your liver, which processes it and eventually stores it as fat. When sugar is released slowly, your body is able to metabolize it and doesn’t store it as fat.
It doesn’t seem like food companies’ interests are aligned with the goal of minimizing processed foods….
You can’t blame the food companies entirely, though, because they wouldn’t make the foods if people weren’t buying them. Consumers demand certain types of products and the food companies respond.
For a while, “low-fat” was the diet buzzword. Then it was “low-sodium,” and now “low-sugar.” Has this led to confusion among consumers about what to eat?
We made recommendations to lower fat in the hope that this would lower people’s calorie intake. But in many foods, fat was replaced with sugar. In the end, these foods weren’t always lower in calories.
How does your research relate to this?
We look at the food supply, including packaged foods and restaurant food – to understand the levels of sodium, trans fats and sugar that are present and how these change as the food supply changes.
We also do consumer research. Under current regulations, food manufacturers can talk about sodium in different ways. We wanted to see how consumers look at the information: do they look on the front of the package, where it might say “low in sodium,” or do they check the back for the nutritional facts? Do they think food that is advertised as “low in sodium” is healthier in other ways – lower in calories, for example? It turns out they do.
We also showed consumers restaurant menus and asked them what they would order. Another day we’d show them the same menu, but this time with calories on it. Would they change their order? Some don’t and some do. For those who do, we ask why and then measure to see if their calorie intake goes down. For those who don’t, we ask why not. We also want to understand who is more likely to change their order – young people, older people or people wanting to lose weight.
Your lab has created tools to give people a better sense of what they’re consuming . . .
Last year we released a salt calculator. And we tell people what their main sources of sodium are – such as eating in restaurants or consuming processed meats. We hope they use the information to adapt their eating habits.
Could you make one for sugar?
Absolutely. The sodium calculator is part of a package of three we did with the University of Ottawa. The first one was about life expectancy. With Given your habits – how much you smoke, drink, exercise, your stress levels and the food you eat – what is your life expectancy? What is the average for a person your age? Then you can play around with it and see what effect reducing the number of cigarettes you smoke each day, for example, has on your life expectancy.
The third calculator concerns hospitalizations: given your habits, how many days can you expect to stay in hospital during your lifetime? We also want to develop apps to help consumers when they’re shopping for food.
And the ultimate goal of all of this?
Improved public health – in three ways: enabling governments to make good policy decisions; helping health professionals educate and treat their patients; and helping consumers make healthy choices.