Losing weight is one of the most popular new year’s resolutions, so we spoke to Dr. David Jenkins, director of the risk factor modification centre at St. Michael’s Hospital (and whose team at the University of Toronto developed the glycemic index), for his advice.
To lose weight, what type of foods should people eat?
The mantra that the nutrition community has accepted is Michael Pollan’s [author of The Omnivore’s Dilemma] one: basically don’t eat too much. A plant food–based diet for people who want to get in shape can be a useful way of going. You can get your fibre with a good dose of vegetable proteins and slow release carbohydrates, which are foods with a low glycemic index. That sounds like a chemical analysis of what you’re going to eat.
What does that chemical analysis translate into when you’re talking about real food?
It translates into eating more fruits and vegetables, especially the leafy vegetables and fruits such as apples, pears, blueberries, blackberries, raspberries, strawberries, these sorts of things. Also foods like beans, peas, lentils, chickpeas make very good vegetable stews or casseroles. Nuts and seeds are the storage foods that give you the healthy fat you need. Even roasted nuts that are salted are not shown to be harmful in moderation. People who consume them have less heart disease and less diabetes.
What about soy products?
People laugh at the “tofurkey” thing that has become a joke, but these soy products are very good and can be used in the same ways that people would use meat. Meat analogues are fortified with things like B-12, which is one of the things that might be absent if one had a diet devoid of all animal products. My advice is to try these things. Try some soy milk!
Why do you think people become so focused on weight loss in January?
In the post-holiday period, many people get into the season of Lent, which traditionally was the season of taking lentils. Lentils are an excellent high-fibre, high-vegetable protein with a low glycemic index that lowers your cholesterol and blood pressure. For thousands of years we’ve depended on foods like lentils. We just don’t eat them now. For thousands of years we’ve remained fairly slim, and recently we all got fat. So there are a few lessons to be learnt historically.
How much exercise do you recommend in a healthy diet routine?
Eating is not the only reason you get fat. New year’s resolutions should also be about keeping fit by exercise. I recommend one hour of moderate to vigorous exercise per day. Other people may say 30 minutes, and I would say that’s the minimum.
How do these recommended foods affect exercise routines?
The foods I’ve mentioned will fill you up. They’ve got a lot of water and fibre, so you’ve got the satisfaction of being full. This is the season of cold weather, so hot soups and vegetable stews go down well. They keep you hydrated, keep you exercising and keep the weight down. Soy products are also protein-rich foods. You’ve got proteins to keep your muscles going, carbs to give you the energy, and if you want fats, take them in the form of nuts, seeds and canola oil.
What’s your take on juicing diets?
Juicing may be fine, but it won’t satisfy a person forever. It could be good if it gets someone started in eating more vegetables for weight loss. It’s also good for portion sizes because they have one cup at breakfast, one at lunch, etc. Measuring is a good way of controlling weight because portion sizes are a big issue.
What portion sizes are recommended?
It’s difficult for me to say how much you should eat with people coming in all shapes and sizes. Basically you should eat so that your body weight to your height ratio (your body mass index or BMI) is less than 25 kilograms to m2 [body surface area metre squared]. Around 22 or 23 is the ideal BMI for most people.
What health implications can occur from dieting?
There are some people who go whole hog onto one particular diet. If they have a wide variety of foods, they are more likely not to come to any particular harm. Some people have low-fibre diets and then eat a lot of fibre, and they will notice a change in bowel habits. For many people that’s a blessing. It’s true for some people there can also be gas and distention, that happens from beans and peas. So there is an adaptation period when you eat these things. It’s worthwhile inching your way into this diet pattern slowly, and be persistent.
Should people consult a dietician?
A visit to a dietician is an excellent one for a new year’s resolution. It’s been my disappointment that dieticians independently are not covered by OHIP. I think if we could get people seeing a dietician on a regular basis it could be a very useful public health measure. Perhaps you’ll have to see a dietician privately for this issue, but it is worthwhile.
