1 June 2014

What's new?

Preventing diabetes with diet and exercise brings healthy heart benefits. 
People with type 2 diabetes have more than twice the risk of death from heart disease than people of a similar age without diabetes. Many studies have shown that diet and exercise can prevent pre-diabetes progressing to diabetes. However, there hasn’t been any high-quality, randomized controlled trial evidence to date to show that lifestyle interventions like this can actually prevent deaths from heart attack and stroke as well. Now, the results from Dr Guangwei Li and colleagues 23-year follow up of the Da Qing Diabetes Prevention Study published in The Lancet Diabetes and Endocrinology, show that participants with impaired glucose tolerance who were randomized to diet and exercise lifestyle interventions had significantly reduced death rates from cardiovascular disease, compared to those randomized to the control arm of the original 6-year study.

Dr. David Katz, director of the Yale University Prevention Research Center, says: “This study shows first, that an intervention focused particularly on diabetes prevention has generalized benefits. This is not very surprising, since the causal and protective factors for all of the prevalent chronic diseases are interrelated. The same diet and activity pattern that helps prevent diabetes does the same for cardiovascular disease. Second, and more surprising, this study suggests that a robust lifestyle intervention program of sufficient duration is a gift that keeps on giving, conferring benefit for years after it concludes. This offers important promise with regard to the cost-effectiveness of such interventions.”

Try exercise snacking for better BGLs.
Exercise science and medicine researchers, including Monique Francois and James Cotter from the University of Otago, Dunedin, New Zealand report in Diabetologia that brief bursts of intense interval exercise before meals (they call it exercise snacking) can help control blood glucose levels (BGLs) in people with insulin resistance more effectively than a daily 30-minute session of moderate exercise. They compared three exercise regimens:

  • 30 minutes of moderate-intensity incline walking before dinner
  • 6 x one-minute intervals of intense incline walking 30 minutes before each meal 
  • 6 x one-minute intervals that alternated between intense incline walking and resistance band exercise 30 minutes before each meal. 
“Sustained hyperglycaemia following meals is an important feature of insulin resistance. Reducing these post-meal spikes is important for reducing the risk of developing type 2 diabetes and its associated complications,” says Francois. “We found exercise snacking to be a novel and effective approach to improve blood glucose control in individuals with insulin resistance. Brief, intense interval exercise bouts undertaken immediately before breakfast, lunch and dinner had a greater impact on post-meal and subsequent 24-hour glucose concentrations than did a single bout of moderate, continuous exercise undertaken before an evening meal. The practical implications of our findings are that, for individuals who are insulin resistant and who experience marked post-meal increases in blood glucose, both the timing and the intensity of exercise should be considered for optimising glucose control.”

Stick with steady aerobic exercise to shift abdominal fat. 
High-intensity interval training (HIIT) is being touted as the fastest way to get lean, but according to University of Sydney researcher, Shelley Keating, only endurance exercise goes the distance for fat loss. Findings of a controlled trial at the University of Sydney’s Charles Perkins Centre published in Journal of Obesity show regular continuous aerobic exercise yields better fat loss results than HIIT workouts for overweight people looking to shed weight and achieve a slimmer waistline.

 “A growing number of people are substituting HIIT for regular aerobic workouts in their exercise routine, but it is not a fast track to quick fat loss if you’re overweight,” says researcher Shelley Keating. “High-intensity burst training does deliver increased fitness, but it doesn’t have a ‘fat furnace” effect if you carry weight around the middle. The message is if you're hitting the gym to lose weight and trim your waistline, stick with steady aerobic exercise to shift abdominal fat and see better results on the scales,” she says. “HIIT can be used as a time-efficient training method to improve fitness, but if you’re overweight you can’t afford to dump aerobic exercise if you want to see fat loss.”

 Group exercising

Exercise extras. 
#1 Prevent diabetes after pregnancy. Women who develop diabetes during pregnancy are more than seven times more likely to go on to develop type 2 diabetes after pregnancy. A recent study in JAMA Internal Medicine, found that sufficient physical activity after pregnancy can cut the risk of progressing to type 2 diabetes by almost half.

#2 Get the low GI edge. A systematic review and meta-analysis presented at May’s DAA Conference in Brisbane (Australia) provides good evidence that low GI foods consumed before exercise enable people to perform longer in an endurance activity or faster in a time trial. “Even small improvements in exercise performance are important at recreational and elite levels,” says researcher Dr Alan Barclay. “Our meta-analysis shows that low GI foods or meals as part of an overall healthy balanced diet can lead to significant improvement in performance.” However, he says, dietary advice needs to be tailored to meet individual requirements.