The 80/20 principle: Get the balance right to get the most from your diet

Anyone who has researched weight loss or fat loss in an attempt to achieve the body they’ve always wanted would’ve read about the 80/20 rule.

The widely accepted definition, also known as the Pareto principle, states that, for many events, roughly 80% of the effects come from 20% of the causes.

In a weight-loss context, the principle suggests that you should focus 80% of your weight-loss efforts on your diet and the remaining 20% on exercise. That’s because exercise in isolation is largely inefficient at reducing weight.

An exercise in futility

Research shows that, in general, there is no or modest weight loss with exercise alone.

Researchers have attributed this to numerous factors. For instance, a study published in the October 2012 edition of Obesity Review found that “the small magnitude of weight loss observed from the majority of evaluated exercise interventions is primarily due to low doses of prescribed exercise energy expenditures compounded by a concomitant (associated) increase in caloric intake.”

What this means is that most people simply don’t have enough time to exercise for the duration required to burn a significant number of calories.

For example, according to information available from the Mayo Clinic, during an hour-long exercise session – the maximum amount of time most of us have on a daily basis to train – a 73kg individual will only burn 533 calories doing high intensity aerobics, 606 calories while jogging, 657 calories on the stepper, or 314 calories while walking.

When you consider that this is the calorie content of just one of your 4-5 small, healthy meals each day, or just two doughnuts if you indulge, you start to realise that exercise is never going to be an effective way to lose weight.

And picking up the intensity of your session isn’t likely to help much either. While you will burn more calories, this merely makes people more hungry, so they eat more after exercise.

Often referred to as “compensation”, this exercise-induced hunger generally cancels out the calories that someone burnt during the session. In fact, many people also tend to consume more calories than they burnt as they reward themselves after a hard session.

Combine exercise and diet

So, should you ditch the gym contract then? Certainly not! There are many other benefits you will gain from regular exercise, be it cardio or weight training, like improved health and a toned, shapely body.

The take-home message is that you should wage war on your weight and body fat in the kitchen, not out on the road or in the gym.

However, there is benefit to a two-pronged approach to weight loss. A 2012 study published in the journal Obesity looked at the effect of diet and exercise, alone or combined, on weight and body composition.

During the year-long study on 439 overweight-to-obese post-menopausal sedentary women, researchers demonstrated that the greatest effects on weight loss and body composition were found in the combined intervention group, where 60% of participants lost 10% or more of their bodyweight in one year.

This means you’ll derive greater benefit from reducing your calorie intake, controlling your portion sizes, and moderating your insulin response by manipulating or reducing your carb intake.

Once you get that element right you can then add the right type, amount and intensity of exercise to aid your weight and fat loss efforts, and help sculpt your body.

Other applications

You’ll also find references to the 80/20 rule as a proposed healthier approach to eating. According to the rule, popularised in the book “The 80/20 Diet” by Teresa Cutter, you must choose healthy foods 80% of the time, and you’re allowed to indulge for the other 20%.

However, this approach is open to abuse and manipulation. For instance, splitting a week up in this ratio means you would eat clean for 5.5 days, and can then indulge for 1.5 days, perhaps over the weekend.

The truth is that a day and a half of uncontrolled eating can easily add back all the calories you’ve ‘cut’ from our diet during the week, so you’re no better off.

A more conservative approach, should you choose to follow these guidelines, would be to add a treat to seven of your meals a week, if you eat five smaller meals per day.

Author: Pedro van Gaalen

When he’s not writing about sport or health and fitness, Pedro is probably out training for his next marathon or ultra-marathon. He’s worked as a fitness professional and as a marketing and comms expert. He now combines his passions in his role as managing editor at Fitness magazine.

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