TORONTO -- It's not every day you see a woman in her seventies demonstrating a deadlift.

“I know many people my age would normally shy away from an exercise like this,” Joan MacDonald wrote in a recent Instagram post.

“I can’t say this enough: surround yourself with knowledgeable people who see the best in you and can get the best out of you! Just because you’re older doesn’t mean you can’t still be pushed and still learn and grow.”

Three years ago, the Cobourg, Ont. native was in a very different place. She weighed close to 90 kilograms (200 pounds) and was on several different medications for high blood pressure and cholesterol. At the same time, she was suffering from arthritis and recovering from knee surgery.

“I was very unhappy with myself,” MacDonald said during an interview with CTV News Channel.

“I had been to the doctors. They wanted to put me on more medication and I didn’t want any part of that.”

That’s when she decided to make a change.

MacDonald joined forces with her daughter, physique transformation coach Michelle MacDonald, and began her six-month fitness program.

Her daughter coached her on healthy eating and worked with her to develop proper technique and form for exercising and lifting weights. She lost 20 kilograms (45 pounds) in six months.

“I am gob smacked,” Michellesaid, speaking to CTV News Channel via Skype from her private gym in Mexico.

“It’s more than just losing weight at this point… she’s actually been gaining muscle. She doesn’t do any hormone replacement therapy – it’s just continuing with eating properly and training with good form, technique, and intensity.”

Muscle is essential to our health and physical function, but muscles naturally start to deteriorate with age -- a condition known as sarcopenia. This loss of muscle is considered a driver for many age-related health issues, but studies show a lack of exercise accelerates the problem.

“It’s amazing to see someone in their 70s putting on muscle, which goes against what we’re told,” said Michelle.

MacDonald, who has amassed over 125,000 Instagram followers, now works out daily and maintains a routine of cardio-based fitness and regular weight lifting. According to her Instagram page, where she documents her fitness regime, she plans out her meals, keeps track of her protein and calorie intake, and makes sure to include every food group.

“Honestly, the trick to the diet plan I’m on is just eating balanced meals like this throughout the day. I eat 5 meals every day, and they are all balanced,” reads a post from her Instagram page.

For seniors who are looking to adopt a healthier lifestyle, Michelle recommends starting slowly and working with a coach to design a workout plan suited for your body and abilities.