Sol Orwell realised he needed to lose weight when he was defeated by a walk in the mountains of South America just 15 seconds in.

Living in Argentina at the time, the 34-year-old tech entrepreneur was visiting Mendoza on the border of Chile when he said, in passing, that he’d like try to climb the tallest peak in South America.

“Both my (now ex) wife and friend basically ‘nah you can't,’” Orwell, who is based in Toronto, recalls to The Independent. “Later on we went to the top of the ski hill, and just running around, I was winded within 15 seconds. It was harsh, but they were right - I was in a terrible physical state.” That was the moment that he realised he had to change.

Sol Orwell at his heaviest

At his heaviest, Sol Orwell, the co-founder of the nutrition website Examine.com, weighed 205lbs. After moving to Argentina, he indulged in the food there - particularly the ice cream. Tearing the tissue in his right knee, he was unable to walk or work the calories off. He had a body fat percentage of between 40 and 45. At 5f 6, he was clinically obese.

Now, he weighs 150lbs and has a body fat percentage of around 12 per cent. Part of his secret, he says is eating a cookie a day.

“They help me stay on point,” he explains. “Having one cookie a day is like a reward. I ate well for the day, so now I get to enjoy it.”

The exercise it takes to burn off high-calorie foods Show all 10 1 /10 The exercise it takes to burn off high-calorie foods The exercise it takes to burn off high-calorie foods Sugary soft drink - 330ml - 138 calories Walk off: 26 minutes. Run off: 13 minutes. JOEL SAGET/AFP/Getty Images The exercise it takes to burn off high-calorie foods Standard chocolate bar - 229 calories Walk off: 42 minutes. Run off: 22 minutes. Koichi Kamoshida/Getty Images The exercise it takes to burn off high-calorie foods Chicken and bacon sandwich - 445 calories Walk off: 1 hour 22 minutes. Run off: 42 minutes. Justin Sullivan/Getty Images The exercise it takes to burn off high-calorie foods One quarter of a large pizza (449kcal) Walk off: 1 hour 23 minutes. Run off: 43 minutes. Getty Images The exercise it takes to burn off high-calorie foods Medium mocha coffee - 290kcal calories Walk off: 53 minutes. Run off: 28 minutes. Getty Images The exercise it takes to burn off high-calorie foods Packet of crisps - 171 calories Walk off: 31 minutes. Run off: 16 minutes. Evan-Amos/Creative Commons The exercise it takes to burn off high-calorie foods Dry roasted peanuts - 50g - 296kcal Walk off: 54 minutes. Run off: 28 minutes. Getty Images The exercise it takes to burn off high-calorie foods Iced cinnamon roll - 420 calories Walk off: 31 minutes. Run off: 16 minutes. Justin Sullivan/Getty Images The exercise it takes to burn off high-calorie foods One bowl of cereal - 172 calories Walk off: 31 minutes. Run off: 16 minutes. Getty Images The exercise it takes to burn off high-calorie foods Blueberry muffin - 265 calories Walk off: 48 minutes. Run off: 25 minutes. Isabelle Hurbain-Palatin/Creative Commons

To avoid gorging at the end of the day, he buys a delicious, fresh cookie instead of a packet.

Orwell adds that one of the most important lessons he has learned since losing weight is that food doesn’t have to be bland.

“In fact, losing weight and delicious food are inexorably linked. By eating delicious things, you are far more likely to stay on top of your diet. And what's awesome is once it starts really coming together and your positivity about it grows, it becomes easier and easier.”

For seven years, Orwell has been maintaining his weight by practising intermittent fasting but stresses that his regime won't work for everyone.

Most of the time he eats a light lunch, works out and then eats a peanut butter and jam sandwich, smoothie, veggies and chicken, or a BLT. At dinner, he makes sure he balances a little fat, carbs and protein by including vegetables, pasta, and meat in his meal.

“Nothing fills you up like veggies do," he adds. "Plus, they really aid your digestive process.”

Orwell also stresses that he eased himself into his new lifestyle. “To start, all I did was buy a pedometer and go for 10,000 steps a day. That's it. Nothing more, nothing less.”

And honing the lifestyle that works for him was a tough process. He tried low-fat, which can lead people to unwittingly opting for high-sugar alternatives. Orwell also tried going ketogenic - a high protein low carb regime - but he just couldn’t stick to either.

“It was frustrating. You'd feel some success, then fail, and think you had messed up.

“The reality was I simply not giving myself something I could stick to for the rest of my life, which people rarely think of when they go on a diet. After all, what happens when you lose the weight - do you start eating poorly again?”

As the weight fell away, he became more motivated to opt for smaller portions and make healthier choices. “Instead of having a double cheese burger, why not a simple cheese burger?” These little things add up.”

“The other important part is to chew your food.” he adds. “Most overweight people actually chew very little. So I put a bite in my mouth, put down my fork or spoon, chew 15 to 20 times, and then prepare my next bite. People often times shovel food into their mouth, and don't spend enough ‘downtime’ between each bite.”

At the same time, he views the so-called clean eating movement where certain foods are labelled as “bad” and “good” as “shortsighted.”

“The moment you decree something is bad, you feel like you've failed. But losing weight is hard enough, and you should feel like you're regularly winning, not failing."

“You need to let loose. I always gain a few pounds when I go on vacation - and I'm happier for it.”

As he indulges in a cookie a day, cutting out sugary drinks, including pop and high-calorie coffees, is also vital to maintaining a healthy weight.

Orwell says, gradually, it has become second nature for him to stay in shape rather than a constant struggle. But he still has to be wary of eating too many sweets.

“I can still binge at times, so buying bulk-bye box of cookies is simply no-go for me.”

The biggest mistake people make when losing weight is rushing in to the process too fast, he warns.

“You feel super motivated so you barely eat, and then five days later you're just dead tired, have completely starved yourself, and go out and binge. Then you feel bad, and it all falls apart.”