There are many supposed quick-fixes when it comes to losing weight. From gastric band surgery to intermittent fasting or strict diet schemes, everyone seems to have a different secret that will help you shift the pounds.

But one woman has just confirmed what most of us always suspected: to lose weight, simply exercise more and eat better and less.

No one said it was easy, but it should be that simple.

25-year-old Amber Barham, a teacher from Florida, was told by her doctor that she should have a gastric bypass after her weight crept up to 275 lbs (19.6 stone).

But mother-of-one Barham decided to ignore the medical guidance and was determined to lose weight on her own.

Simply through overhauling her diet and exercising, Barham lost 100lbs in 18 months.

From the age of 23, Barham had been on blood pressure medication, and when her doctor suggested she have the drastic surgery, it was the wake-up call she needed.

Her weight had crept up thanks to a combination of a thyroid condition and a diet consisting largely of pizza and sweets.

Now, however, Barham works out six times a week and eats home-cooked meals instead of junk food.

18 months since overhauling her lifestyle, she’s got her weight down to 175 lbs (12.5 stone).

After being diagnosed with the thyroid condition, Barham had accepted the fact that she would probably always be overweight.

“There isn't a time that I could say I wasn't overweight but I have also struggled with thyroid problems my entire life,” she said.

“I think my thyroid condition was used as a crutch in some ways, and it made me believe I was just always going to be overweight. I was 23 and put on blood pressure medicine, and my doctor suggested I have gastric bypass.

“This made me believe that he thought I wasn't capable of losing the weight, so I proved him wrong.”

Like many people who seem to have a healthy relationship with food and their bodies, Barham follows the 80/20 rule: 80 per cent of time time she eats healthily, and 20 per cent of the time she lets herself indulge a little more.

It’s a simple approach that has brought about huge results for Barham.

“I can shop for clothes I want without worry,” she said. “I could never do that before. I also feel that I can inspire others by showing them that anything is possible if you put your mind to it.”

And one of the places she’s inspiring others is through her Instagram account, where she’s sharing her progress.

“I feel a lot more confident than I ever have in my life,” Barham added.

Seeing results is encouraging, but the hardest part of a weight loss journey is staying motivated when the numbers on the scale stop going down. Barham says the trick is to start by setting little goals that aren’t too daunting.

“Plateaus are the hardest part about losing weight hands down, it can be very discouraging to be doing everything right and to see the scale not move or it go up even,” she said.