Prof Jennie Brand-Miller answers your questions.
If carbs increase my blood glucose levels, wouldn’t a low-carb diet (or even a very low one) make better sense for managing it?
I am often asked about this. In theory, a low-carbohydrate diet seems a logical choice if your aim is simply to reduce blood glucose levels. But presumably your goal is long-term, optimum health with good glycemic control and reduced risk of chronic disease. If so, very low-carbohydrate diets need a little caution because you will be missing out on the micronutrients, antioxidants, phytochemicals and fibre that plant foods (fruit, starchy vegetables, legumes and grains) provide. In studies that tracked individuals for long periods of time, those eating the least amount of carbohydrate and very high amounts of protein had almost double the risk of dying during the follow up period, especially from cardiovascular disease. You might also find this very low carbohydrate diet so extreme that it's hard to lead a normal social life and enjoy eating because you have to exclude so many favourite foods (think potatoes, oranges and honey).
The authors of a critical review recently published in Nutrition in July 2014, call for a complete reappraisal of dietary guidelines for diabetes management and they present evidence for dietary carbohydrate restriction as the first approach in diabetes management. Some of these authors have themselves adopted a very low-carb diet to manage their blood glucose. I do think there is some truth in the benefit of modest reductions in carbohydrate intake (to say 40–45% energy). However, I’m not in favour of further reduction because it’s just too hard for most people to comply. Conversely, I'm not recommending an increase in carbohydrate intake to 65% of calories to someone with diabetes; it strikes me as "pushing the envelope" too far.
Apart from being difficult to sustain over the long term, a major concern with very low-carb diets is the potential for high saturated fat intake and its health repercussions. Even a single meal high in saturated fat can have an adverse effect on blood vessels by inhibiting vasodilation, the normal increase in the diameter of blood vessels that occurs after a meal. In meta-analyses, the short-term and long-term effects of a low carb diet includes an increase in LDL cholesterol. Compounding this, there may be a low intake of micronutrients that are protective against chronic disease. For this reason, a vitamin and mineral supplement is usually an essential accompaniment to a low carb diet.
I believe that very low-carb diets are unnecessarily restrictive (bread, potato, rice, grains and most fruits are off the menu) and may spell trouble in the long term if poor quality food takes the place of high quality carbohydrate. Modestly higher protein/low GI diets strike me as a happy medium between low fat and low carb-diets – you can have your carbs, but choose them carefully.
World’s Best Diet.
This is a diet without deprivation that’s designed to satisfy the senses as well as the stomach. The book is based on the Diogenes study, one of the world’s largest dietary studies, and combines a higher protein intake with low-GI carbs, which has been proven to prevent weight regain creep. Explaining how it works, the authors say: “Our research, and that of other nutrition scientists, has shown that the body’s food regulation mechanisms are quite complicated, but that one thing is quite simple: in order to sustain our weight over periods of months and years, we have to stay satisfied and enjoy food – preferably three times a day. A food culture that leaves out whole food groups is simply too restrictive for enjoyment and long-term sustainability ... The less restrictive a dietary change is, and the less prohibitive of common foods it is, the easier it is to stick to. The ‘state of slim’ requires enjoyment, and this is wonderful news for dieters everywhere.”
The authors have carried out numerous studies over the past 20 years looking at ways to create greater satiety with fewer calories and without eliminating entire food groups. They write: “If we can eliminate constant hunger pangs and create enjoyable satiety, we have the best defence against overeating. In other words, the solution to successful long-term weight control is to feel full and satisfied at the end of eating, and then hunger should take hours to return.” The five key principles of World’s Best Diet are:
- Eat fewer carbohydrates and more protein than you currently eat. The ideal ratio of carbs to protein is 2:1.
- Opt for low-GI carbohydrates instead of high GI ones.
- Limit your intake of saturated fat.
- Choose low-fat dairy products.
- Eat whole-grain products, the less refined the better.
—World’s Best Diet by Christian Bitz and Professors Jennie Brand-Miller, Arne Astrup and Susan B. Roberts (Penguin Australia) is available from bookshops and online. It includes menu plans and 92 recipes and is fully photographed throughout.
“Beevangelist,” Doug Purdie, has written a comprehensive guide to keeping bees. He reckons that once introduced to the charms of beekeeping and the taste of warm honeycomb direct from the hive, you’ll be hooked. His book covers installing and maintaining a hive through the seasons and includes stories from enterprising beekeepers from all walks of life plus 20 recipes for all that honey you’ll be harvesting. Doug, along with his partner at The Urban Beehive, maintains more than 50 beehives on city rooftops, balconies, backyards and in community gardens around Sydney. He runs beginner beekeeping courses and is president of the Sydney branch of the Amateur Beekeepers’ Association.
—Backyard Bees by Doug Purdie (Murdoch Books) is available from bookshops and online.