Kayla Itsines is sick of "ignorance" about the benefits of exercise.

Alongside snippets of her now world-famous workouts and recipes, Kayla Itsines‘ Instagram feed features plenty of before-and-after photos of women following her Bikini Body Guide (BBG) plan.

Most of these images document the physical effects of the personal trainer’s popular eating and fitness guide — weight loss and muscle tone, to be more specific.

This focus on the aesthetic ‘transformation’ that comes with exercise isn’t unique to Itsines’ followers; a quick glance at the #fitspo hashtag on Instagram suggests it’s a major drawcard for many young women.

However, the Adelaide-based fitness guru insists her love of and dedication to exercise isn’t centred on losing weight or looking ‘skinny’, and that for for some reason many people struggle to accept this.

“For some people it can be hard to talk about health, fitness and exercise as their passion because … [they] don’t quite understand it. I always hear others saying, ‘Oh, but you’re already skinny, so you don’t need to exercise,’ or, ‘Don’t you have better things to do?’” Itsines writes in a new blog post.

“I think these types of sentences come with a little bit of ignorance sometimes, simply because that person doesn’t fully understand the reasons behind exercising.”

Watch: Sam Wood demonstrates a simple bodyweight circuit you can do at home. (Post continues after video.)

Itsines argues that the mood and confidence-boosting powers of exercise are reason enough to get started.

“If you are feeling anxious or angry or just need a little pick-me-up, try going for a long walk out in nature or bust out a few body weight exercises in your living room and feel the difference,” she writes.

“While the thought of doing burpees after a tough day at the office may not sound like your idea of a fun time, a workout (even a quick one!) can help you feel so much better.”

It’s so good to have personal goals! For me, I wanted to be able to do chin ups. I did my normal #bbg workouts during the week and then adding in a few of these?, some pull up holds and general back exercises. Eventually I was able to do TWO full pull ups …and from there, slowly improved my technique to be able to do more and more ?? What’s your personal goal? www.kaylaitsines.com/app

A photo posted by Kayla Itsines (@kayla_itsines) on Mar 24, 2016 at 12:18pm PDT

Of course, the effect of exercise on weight and body shape is appealing for a lot of people, and that’s not necessarily a bad thing. Yet there are other scientifically-proven physical benefits worth focusing on, Itsines points out.

“As well as improving quantity of life, can also improve quality. For example, weight-bearing exercise (such as cardio and resistance training) has been shown to help strengthen bones, which can help to prevent arthritis and decrease falls later in life,” she explains.

“Not only is regular exercise great for your general health, but it may improve your ability to complete daily activities and prevent injuries. Things such as climbing stairs, doing the groceries or even playing with your kids are just a few examples.” (Post continues after gallery.)

Itsines makes an important point here. Although it can be gratifying to observe how physical activity changes and shapes your body, remember there are many, many other reasons to keep fit and active for your body and your mind.

Just because you can’t see those results in the mirror, doesn’t mean they’re any less important.

Why do you exercise?