Chief among those countries revelling in a disastrous diet high in fats, salts and sugars but low in physical activity is Ireland, where 30pc of 11-year-olds are now deemed to be overweight.
But at the same time, sales of diet and fitness books are soaring – up 50pc last year – we've more knowledge on healthy eating and greater access to gyms compared to previous generations.
We even have greater access to a wide range of foods and more disposable income than our grandparents – so why are so many of us fat?
Two out of three Irish adults are overweight, with experts predicting that half the country's over-18 population will be categorised as 'obese' by 2030.
Considering we're living longer and know more about nutrition, we should be healthier than ever.
"The level of education is good and you would expect the situation to be different, but that's not the case," says Professor Donal O'Shea, obesity specialist with the HSE and Director of the Weight Management Clinic at St Columcille's Hospital in Loughlinstown, Co Dublin.
"There are two main reasons," he explains. "There has been a massive decrease in the level of physical activity over the last 30 years and it's happened in parallel with a big change in the way we eat and what we eat."
Our grandparents might have walked everywhere and survived on meagre portions of simple food but that's not how we do it today.
The 2011 census shows that car ownership has been rising steadily since 1986, we're more dependent on private vehicles when commuting to work and the proportion of primary, secondary and third-level students walking to school or college has maintained a long-term pattern of decline. It is now estimated that just one third of the population of Ireland is meeting the recommended weekly levels of moderate physical activity: 150 minutes.
Portion sizes have grown, there's more high fat, high salt, high sugar foods on the market and the boom in technology means we're spending more time in front of screens than out and about.
Whilst our grandmothers' roles may have been focused solely on the home, cultural changes mean more women are now in full-time employment and a rise in shift work means it's not always possible to provide a home-made, sit-down family meal every night – even though studies consistently show that children who eat with the family are less likely to be overweight.
Culturally life has changed and it's showing on our waistlines, but one of the most worrying aspects of Ireland's growing obesity problem is its grip on the younger generation.
One key problem is that children are often being given control to make decisions that would have been unthinkable generations ago.
"There is a huge need for parents to take responsibility for what their child eats," says Professor O'Shea. "High-fat, high-sugar foods generate cravings, especially for kids and left to their own devices a child will almost always favour this option. Up to the age of 12, parents should be responsible for what their child eats.
"A parent wouldn't let their three-year-old smoke or drink alcohol, but there needs to be a similar level of importance given to making sure their child is eating healthily and getting physical activity – because the health threat is equal."
Ruth Charles, a consultant dietitian specialising in paediatrics (nutrikids.ie) agrees. "Many parents argue that they have the right to feed their families whatever they like, that it's their choice," she says. "But with choice comes responsibility and for every choice there's an effect.
"Relying heavily on ready meals, deli sandwiches, takeaways and so on means a larger than ideal intake of calories, fat, salt and sugar, high food costs and higher risk of weight gain, heart disease and certain cancers."
Aled Hughes' private consultancy business (aledhughes.ie) is currently oversubscribed with children who need to get fitter. He says focus on exercise has changed in education.
"Physical education in primary schools in Ireland is not as strong as it could be," he explains.
"Yes, it needs to be fun, but we don't challenge the majority on their physical fitness capabilities. We need to bring the PE curriculum into the 21st Century by giving teachers tools to challenge and test the children within a school academic year."
Nutrionist Heather Leeson from Positive Nutrition (positivenutrition.ie) runs a Fat Around the Middle course aimed at changing eating habits and reducing abdominal obesity. She says we also have a major problem understanding the labels on many new products, particularly when it comes to sugar.
She says: "While many people are aware that they need to cut down on treats, they are not aware of the high levels of sugar in convenience foods.
"A healthy-looking low-fat or diet yogurt could contain as many as seven or eight teaspoons of sugar per pot and many breakfast cereals have as much sugar as a chocolate bar."
But is Ireland more at fault than other nations? The WHO rated Greece, Portugal, Ireland and Spain as having the highest proportion of overweight 11-year-olds.
The Organisation's director for Europe, Zsuzanna Jakab, says it's because being overweight has become normalised as has a culture of convenience, high fat food.
But Ireland's history may also be conspiring against our nation's waistlines. "We're not that many generations removed from going through a famine," says Professor O'Shea. "Starvation was the ultimate threat and those who survived did so by storing energy – we now have a population that is very good at storing energy."
We've also turned into a nation of chocoholics with a 2012 report by Food from Britain showing that Ireland has the highest per capita consumption of chocolate in the world, with approximately 24.7lb of chocolate gobbled down each year, per person.
"Junk food and sugar-laden snacks are more widely available here than in other European countries," says Heather Leeson. "This means there is much more temptation for even the most committed of healthy eaters, whether you are buying the paper or filling up the car."
Unfortunately it's the sweet treats that are making us fat. "Abdominal obesity is fuelled by a high sugar diet," adds Leeson. "Having a muffin or scone with your coffee every morning isn't a treat. It's an unhealthy habit that could cause you to gain up to a stone in a year."
Paradoxically another cause of our obesity is societal pressures to be super-svelte.
"We've done psychological evaluations at the clinic and found that overweight people often score highly on 'perfectionist'," says Professor O'Shea.
"There's an attitude that 'if I can't be spot on then why bother?' but we have to try and educate people in the importance of modest change and dedicate more resources towards promoting healthy eating and cooking because the reality is obesity is a preventable disease that we're allowing to kill thousands of people."
HOW THE STARS STAY SLIM
"For me, staying in shape is about controlling portion size ... I don't deny myself foods I love, like cheese and pizza, but if I want to drop a couple of pounds, I'll reduce the portion size of everything I eat."
Colin Farrell (on getting in shape for Total Recall)
"I ate lots of greens and chicken, I didn't order dessert for four months. I stayed off sugar and got myself on the treadmill."
"I'm not into any fad eating regimes, I just eat well and avoid bad foods."
"I tend to do boxing training: jump rope, focus mitts, heavy bag, push ups, reps, high intensity."
"I walk everywhere which saves me money on transport and that's how I get my exercise."
"If you tell yourself you can't have something, it doesn't work.
Your mind is stronger than your body and before you know it, you've got a bucket in your hands.
"I wish I'd known when I was young that if you just eat healthy, wholefoods you can eat any amount you like and you'll be fine."