As we head into summer, our minds turn to thinking about how to squeeze into the same swimwear we wore last year. Our new health minister Jonathan Coleman has the goal to ‘slim the nation’, by bringing together his roles as Minister of Health and Minister of Sport. Sadly his goal is pointless unless he is willing to deal with the elephant in the room – fake food.

No, Minister

Coleman was a doctor in his former life, so he knows the challenges our health sector faces from a population with a bulging waistline. Obesity is overtaking smoking as the greatest preventable risk to our nation’s health. Along with that comes a host of health problems – diabetes, heart disease, cancer. This is likely to hit at the same time as our baby boomers retire, and want their hip and knee operations.

Sadly, the good doctor has diagnosed the problem but is blind to the most obvious remedy. The fact is that exercise alone cannot solve the obesity epidemic, we have to deal with the abundance of cheap, convenient fake food – food that is laden with energy but bereft of goodness.

The Minister needs to go back to medical school to brush up on the facts, and stop dishing out placebos.

We can’t all jog our way to health

The idea that exercise can purge all our dietary sins is an appealing one, but it is wrong. Let’s start by looking at the numbers. Ministry of Health estimates that poor diet costs Kiwis about 110,000 years of life every year. By contrast lack of exercise costs about 40,000.

That means that in terms of lifestyle, exercise is ¼ of the problem. Fake food is the real issue.

This result is borne out by diet studies. Most people who successfully control their weight get some exercise almost every day, but while exercise may be necessary for health, it is not sufficient in itself.

In other words, most people don’t lose weight (and keep it off) through exercise alone. You have to control your diet.

Lazy Policy

This simple fact means that a policies dedicated to reducing our weight through exercise are a waste of money. They might look good. They might make us feel better because the Minister and Government is ‘seen to be doing something’. But without sorting out what we eat these policies won’t be effective.

We know that focussing on improving our diet is a far more effective way for the government to spend its limited funds. In fact, putting a tax on soft drinks and other fake foods, as is happening overseas, is doubly effective – it reduces the amount of junk we eat and raises money at the same time. That, dear Minister, is cost effective.

So why are we putting all our effort into something that is only ¼ of the problem, when we know that it isn’t a solution? The answer is politics – exercise is a far easier thing to focus on, as there are no losers. Changing the way we eat risks denting the profits of fake food manufacturers. The Minister is being weak willed, and wasting our taxpayer dollars at the same time.

Why is diet more important than exercise?

How can this be? We all know that weight control is a simple matter of balancing energy in and energy out. So surely exercise plays a role. The food we eat is the source of energy for our bodies, but the amount of exercise we do is one determinant of how much energy our bodies actually need. If you exercise more, you can eat more. Woohoo! However, there are several reasons why focussing on exercise doesn’t mean you can eat whatever you like.

Exercise makes little difference to your energy needs

Firstly, while exercise adds to your energy needs, the difference it makes is surprisingly little: a 40-minute run for most people only adds around a quarter to the daily food energy you need. This may seem strange, until you understand that you actually burn most of your energy just by going about normal daily life. For most people just keeping your body working (even lying down) takes up between half and two thirds of the energy you release. For example, your brain only makes up 2% of your body weight but it burns about 18% of the energy you eat. You can see why our forefathers developed a taste for sugary and fatty foods in order to feed their growing, energy hungry brains.

The benefits of exercise can be wiped out in a moment of indulgence

Thanks to the energy packed into modern fake food, all this hard work can be wiped out in an instant with a little indulgence. Some examples:

• As we pointed out in our infographic, it takes a 60 minutes of walking to burn off a bottle of Coke or a solitary muffin.
• Drinking a ‘sports drink’ to ‘rehydrate’ after a run wipes out 20 minutes worth of jogging.
• It takes a person 20 minutes to sip away a glass of chardonnay or pinot noir, but 30 minutes of walking to work it off

In other words if you ‘reward’ yourself with a supposedly healthy sports drink and muesli bar after some exercise, you have probably wiped out the benefits of that workout.

You start to see how easy it is to fill your internal warehouse faster than it’s emptied by energy requests, and to snack or sip your way to obesity. Unless you have the time to train like a competitive triathlete, most of us can’t expect to exercise enough to allow us to eat or drink what we want. That is why dietary control (restricting the shipments of energy into your warehouse) is by far the most potent weapon in the battle of the bulge. And yes, that includes alcohol and soft drinks, which are often overlooked as a source of calories.

Exercise makes you hungry

Another issue for proponents of exercise is that they assume exercise has no impact on your appetite. It doesn’t take a genius to realise this is a complete fallacy. The body naturally compensates for exercise by eating more or exercising less over the rest of their day, which can render any sweaty exertions in the gym futile.

In fact it seems the best way to ‘fool’ your body into exercising without compensating for it is by making exercise part of your day to day lives. Having a job where you are on your feet is a great help (and if you are desk bound – try a standing desk!). Walking or cycling to work, or even getting off the bus early and walking the last stretch to work are great ways to get your heart rate up. Of course, whether or not people can do that depends how safe and easy those options are. But they are worth doing, because those of us locked into a sedentary lifestyle are even more vulnerable to the damage wrought by indulgent diet.

We are not bagging exercise at all, simply identifying its limitations. Exercise is really important and has benefits far beyond helping to balance out your food intake: including building muscles and bones, heart health, and even making you happier. And if you exercise to work up an appetite, then fill up on decent tucker rather than fake food, you will benefit from the extra nutrients. But exercise simply isn’t a magic charm that can absolve you from the ill effects of eating whatever you like.

So if the Minister is serious about tackling obesity, he needs to think seriously about what the nation is eating. Otherwise his policy is just like going for a jog on a treadmill – it creates a lot of hot air, but it’s not going anywhere.