The obesity epidemic in North America is a well-established phenomenon, and its deleterious effects on the health-care system are similarly acknowledged, from increased rates in cardiovascular diseases, diabetes, stroke, heart attack and others.
Less than 21 per cent of adults currently meet the basic recommendations for adequate exercise, and the rate of health-care problems in sedentary children continues to rise.
When considering putting a weight loss program into action, most people wonder not only what are the most effective methods to achieve their goals, but how to do it efficiently – attain the greatest impact without necessarily having to devote a great deal of time or fuss in implementing the plan.
A study published last year in the Journal of Diabetes and Metabolic Disorders looked at a variety of these variables to determine the effectiveness of different interventions in reducing body fat in the obese population. It was a meta-analysis paper, which means that it looked at a large number of good quality research studies (66 populations-based studies) with common research aims and objectives.
The study looked at the difference in effectiveness in reducing body fat (while maintaining or increasing lean muscle mass) of the following interventions: resistance exercise, endurance exercise, diet and various combinations of these variables. It also compared some subsets of these, namely low vs. high intensity exercise and low fat vs. high protein vs. glycemically controlled diets.
The study made a number of conclusions. They found that exercise, by itself, created a greater effect on healthy weight loss (loss of body fat with no loss of muscle mass) than any single specific diet intervention. They found exercise was also more effective at positively changing hormonal signals and blood lipids toward normal function than diet, and that as the intensity of exercise increased greater positive changes were made on insulin resistance and other markers of metabolism.
The study uncovered that resistance training (lifting weights, doing push-ups) was more effective at producing fat loss than endurance training at less than 70 per cent maximal effort (cycling, swimming, walking for example). When the intensity of these endurance exercises increases to levels above 70 per cent, then the fat loss effect becomes similar to resistance training.
This trend also held if these high intensity endurance exercises were done, by either sustaining the intensity for at least 20-30 minutes or by performing interval training. That means doing short bursts (20-60 seconds) of high intensity followed by a recovery period of one to two minutes of moderate intensity 50-60 per cent of maximum.
This is good for beginners to exercise.
Higher intensity effort produces burning sensation and discomfort in muscles, increased heart rate, breathlessness and general feelings of distress along with the post-exercise stiffness and soreness. These sensations, though completely normal and natural, produce avoidance behaviours in those new to exercise.
But when high intensity is performed in short intervals it produces a beneficial effect while mitigating some of the uncomfortable side-effects.
In my experience, exercise discomfort is one of the main disincentives to start or maintain an effective exercise program.
All of the interventions produced positive results, and when both diet and exercise were combined as an intervention, it was more effective at producing positive body composition changes than any type of single exercise or diet regimen alone.
Obesity is a complicated, multi-factorial condition, both with regard to its causes as well as its treatment. Each person has their own genetic predispositions and individual differences, so no single approach will suffice.
It’s up to the individual to address the situation with the best evidence based tools available.
If you are considering high intensity exercise and you have health conditions which would be adversely affected, seek advice from your doctor before starting.
– Kerry Senchyna holds a bachelor of science degree in kinesiology and is owner of West Coast Kinesiology
in Maple Ridge.