For ages, we've been told that being a couch potato will make you fat. Some of the latest obesity-related news to hit the headlines, however, flips that notion on its head.
Because it turns out, according an editorial by a group of international experts in the British Journal of Sports Medicine, this is not true at all: while obesity has ballooned in the last 30 years, we've not become any more - or any less - active.
Instead, they point the finger firmly at the current villain of the food world, sugar, and its bedfellow carbohydrate.
Basically, according to them, you can still be a couch potato, just don't overdo the chips and ice cream.
CALORIES ARE NOT EQUAL
Apparently, the public have long been mis-sold the 'myth' that all calories are equal, when in fact, sugar is not filling, leaving people feeling they need to eat more, and is linked to type 2 diabetes.
The experts also say athletes are at risk of developing type 2 diabetes, because they're filling up on carbs, when they'd be better off on a high-fat, low-carb diet.
SO SHOULD WE DITCH CARBS?
Can this all be true, and should we be foregoing carbs for good? We asked two nutritionists to sort the wheat from the chaf...
* Rob Hobson, registered nutritionist and co-author of The Detox Kitchen Bible says: "I don't go along with that whole anti-carb diet idea - ask anyone on the Dukan diet, you feel knackered - and the wholegrains have too much goodness to give them up.
"There's definitely a shift towards eating fewer carbs. But if you're cutting out carbs from your diet, you're also missing out on key nutrients, including B vitamins, which convert food into energy, and help to fight tiredness and fatigue.
"It wouldn't work if athletes had a low-carb diet, because they need to replace energy in muscles.
"Sugar is a simple carbohydrate, and it's bad because it's linked to spikes and troughs of insulin. The carbs that aren't as bad are the complex ones, because they have high amounts of fibre, which has less of an effect on your blood glucose levels.
"Not all calories are created equally, there's nothing in sugar except energy, so gram for gram, you're better off eating wholegrain carbs.
"I recommend you include carbs in your diet, but stick to wholegrains, pulses and beans, because they are a valuable source of fibre, which protects against illnesses such as colorectal cancer.
"White carbs, like pasta and refined flour, will fill you to start with but are broken down quickly, so they'll make you feel hungry and quite sluggish. But white carbs can be beneficial for some, including young children, who don't need too much fibre.
"There's a misconception that carbs are high in calories. Calories come from what you put on the carbs, so that's partly the reason that you put on weight with carbs.
"If you need to lose weight, I recommend filling up on veggies, because they've got a lot of bulk and fill you up."
* Dr Marilyn Glenville PhD, nutritionist and author of Fat Around The Middle, says: "I would definitely agree that sugar and carbs are causing the obesity crisis. Exercise has health benefits, including reducing the risk of cardiovascular disease, type 2 diabetes, certain cancers and also Alzheimer's, but people are fighting a losing battle with obesity and being overweight if they are still eating the sugar and refined carbs.
"The problem is that sugar and refined carbohydrates hit your blood stream quickly, causing a high rise in blood sugar.
"The result is higher levels of insulin being released from your pancreas, and insulin tells your body to store fat.
"All forms of carbohydrate end up being broken down into glucose, but it's the speed with which this breakdown happens that's crucial to weight gain [known as the Glycaemic Index; GI].
"Refined carbohydrates are foods like sugar, white bread and glucose added to sports drinks.
"Unrefined carbohydrates give you greater, longer-lasting energy and stable blood sugar because your body digests them more slowly. These come in the form of brown rice, oats and rye.
"You can add 'fake' starchy carbohydrates to your diet in the form of spiralised courgette pasta and also quinoa.
"Quinoa cooks up like rice so can be used like a starchy carb, but it is actually a seed and high in protein and rich in vitamins and minerals."