

By Stuart Marsh|

Calories in, calories out doesn't tell the whole story.

The calories-in-calories-out (CICO) theory of weight management is simple: if you eat more food than you need, you'll get fatter. Eat less than you need, and you'll get skinnier.

This is, of course, a gross oversimplification of how our bodies work. Everybody needs a different amount of food, and everybody processes that food a little differently – but the basic equation still always applies at a big-picture level.

Knowing this, many people then wonder: is it possible – considering all calories were equal – to lose weight eating only junk food?

The answer (fortunately or unfortunately, depending on how hopelessly addicted you are to Snickers) is yes – but you'll probably feel absolutely terrible doing it.

To find out why, we posed this hypothetical question to the dietitians: What's the difference between 1000 calories of healthy food, and 1000 calories of junk food?

According to The Nude Nutritionist and dietitian Lyndi Cohen, there's a multitude of differences – the main one being how your body actually uses the food you put in your mouth.

"If you're eating 1000 calories of junk or processed food, your body won’t actually process the energy the same as if you were eating 1000 calories of whole foods," Cohen tells Coach.

"For instance, if you were to have a 200-calorie piece of chocolate cake, those calories would be absorbed differently compared to 200 calories of nuts.

"Because nuts are a wholegrain packed with fibre, it's estimated that 10 to 15 percent of those calories won’t be absorbed at all."

You'll build more muscle

When it comes to being as healthy, (and frankly, as good-looking as possible) having an adequate amount of muscle mass is key. This doesn't mean you have to walk around looking like a competitive bodybuilder, but the more muscle you can keep on your frame the less likely you are to become injured, sick or frail.

"For wellbeing, it's the quality of the calories you're eating that matter," Cohen tells Coach.

"If you eat a diet that's high in protein and fibre and nutrients, you're much likely to build and retain muscle mass, which burns calories even when you're resting.

"Conversely, if you eat a diet high in sugary, processed foods high in unhealthy fats, you're likely to lose some of that muscle mass and generally not look or feel as good."

Your energy will be more sustained

Technically, 1000 calories of processed food contains exactly the same amount of raw energy as 1000 calories of healthy food – after all, a calorie is defined as being the amount of energy that's required to raise the temperature of one gram of water by one degree Celsius.

So no matter whether you're eating Mars Bars or salads – provided they're both equivalent to 1000 calories – you're still getting the same potential energy.

But as Cohen explains, if you choose to eat your total days' worth of energy in Mars Bars, you're essentially telling your body that you've decided to dump all of this energy at once, instead of slowly releasing it in timely bursts over the day.

"If you were to eat 1000 calories totally from processed food, you're likely to go through peaks and troughs with your energy, and feel hungry for much of the day," explains Cohen.

It's a sentiment that sports dietitian Alison Patterson agrees with, arguing that just because a food is dense with calories, doesn't mean it has the nutrients required to keep you going.

"Highly processed foods are typically low in fibre which can lead to gut issues such as bloating and stomach pain," Patterson tells Coach.

"It’s also likely that you’d feel fatigued as many of the essential nutrients needed for good health —such as iron and other vitamins and minerals — are often lacking in heavily processed foods."

You can eat bigger meals

The biggest difference between 1000 calories of junk food and 1000 calories of nutritious food isn't so much avoiding the inevitable sugar coma – it's in the sheer amount of food that you actually get to eat.

As Cohen explains, because foods like chips, sugary drinks and fast food are so calorie-dense, you simply don’t get to eat as much for the same bodily "cost".

"It's what we call food volume – 1000 calories of healthy food will fill up potentially a few plates, where 1000 calories of junk food would look tiny in comparison," says Cohen.

"Plus, because the healthy food is likely to contain wholegrains, healthy fats and protein, so you're much more likely to be satiated and you won’t feel hungry again soon after eating."

Your body composition will be better

If you're looking to lose sheer weight, then making sure you're eating less calories than you need is key. But if you simply want to look better – no matter what the number on the scale is – then you'll need to focus on building muscle mass, and losing fat.

The best way to do that, unsurprisingly, is to improve the quality of your diet. As Cohen explains, we're beginning to understand that the type of foods you eat can actually play a role in how your body stores fat.

"Research has shown that a diet high in processed foods could actually cause your body to store more fat – particularly around your stomach." says Cohen.

"Essentially, if you can sacrifice the instant gratification of processed foods you'll reap all the rewards of long-term health – like more muscle mass, improved mood and lower risk of chronic disease – from healthy foods."
