The Science Behind Exercise: Why Moving Your Body Changes More Than Your Weight
Updated: Aug 27
Smart Health Key 10/12 – Move Your Body for 30-60 minutes Every Day
If you've ever started exercising because you wanted to lose weight, you'll probably recognise this moment...
You finally commit. You start walking every morning, join a gym, dust off the exercise bike in the garage, or promise yourself that this is the year you'll become more active. For a few weeks, you stick with it. Then you step onto the scale... and it hasn't moved nearly as much as you'd hoped.
It's frustrating. You start wondering whether all the effort is even worth it.
But here's what many people don't realise: exercise is about far more than burning calories.
Weight loss is just one of the many ways your body benefits from regular movement. In fact, some of the most important changes are happening long before you notice them on the scale...
That's because you first build a bit of muscle, while starting to lose fat, so even if you weigh the same the first while, you already feel and look slimmer and fit into your clothes better!
Exercise helps you feel better long before you look different
One of the first things many people notice isn't a smaller waistline—it's that everyday life starts feeling easier.
Walking upstairs leaves you less out of breath. Carrying shopping bags isn't quite as exhausting. You have more energy to keep up with your children or grandchildren, and by the end of the day you don't feel quite so drained.
Just like my client Barbara
Barbara Steenkamp came to see me when she was >100kg, had high cholesterol and a fat% of almost 50%.
I coached her to eat a low GI, lower fat, balanced diet with plenty of veggies (instead of cutting out carbs) and start walking regularly again.
Over 18 months, she gradually lost 30kg (66 lbs) of fat.
Her cholesterol and fat % are normal now, and
she's kept her weight down for years.
She enjoys the Smart Health Diet lifestyle and cooks & bakes recipes from our Eating for Sustained recipe books. Now she can enjoy activities with her granddaughter again!
That's the power of regular exercise.
Regular exercise builds strength, stamina and flexibility - making the ordinary tasks of life feel less like hard work.
It also helps to reduce stress, improves your mood and encourages the release of endorphins—the chemicals responsible for that wonderful sense of well-being after a good walk or workout. On top of that, it raises the good HdL-cholesterol, that works like a "broom" for your arteries, "sweeping out" the bad fat and removing them from your body.
Quite simply, people who move regularly tend to enjoy life more because they have the energy to participate in it.
Yes, exercise burns calories—but that's only the beginning
Of course, exercise does help with weight management. Walking briskly for about an hour burns roughly 1,500 kJ (350 Calories)—the equivalent of about five slices of bread.
Done consistently, that makes it much harder for excess body fat to accumulate over time. But here's the part many people overlook...
When you exercise, your body continues using extra energy even after you've finished.
And if you include some strength or resistance training, you gradually build lean muscle. Muscle is metabolically active tissue, which means it uses more energy than fat, even when you're resting.
Think of it as upgrading your body's engine. A stronger engine naturally burns more fuel. That's one of the reasons exercise makes long-term weight management so much easier than relying on your diet alone.
You don't need the perfect workout
People often spend so much time looking for the "best" exercise that they never actually get started.
The truth is, the best exercise is simply the one you'll still be doing a year from now.
Whether it's walking, dancing, cycling, swimming, gardening, playing tennis, hiking, Pilates, Zumba or going to the gym doesn't really matter. What matters is finding something you genuinely enjoy enough to make it part of your life.
Health isn't built through occasional bursts of motivation, but through consistency.
If you're new to exercise, start small
One of the biggest mistakes people make is trying to change everything overnight.
They decide they're going to exercise six days a week, push themselves to exhaustion, spend hours in the gym... and two weeks later they're too sore, too busy or too discouraged to continue.
There's a much better approach. Start with what feels manageable. Build the habit first. Just like you'd never say that you don't have time to take a shower or brush your teeth, because it is a priority, you won't easily skip your daily exercise/activity once it's a priority.
Once regular movement becomes part of your routine (a good habit), increasing the intensity becomes much easier.
Remember, your goal isn't to survive one difficult month. It's to build a lifestyle you can maintain for years.
Exercise and healthy eating work together
Many people think of nutrition and exercise as two separate things. They aren't.
They support each other.
If you don't exercise regularly, slowly digested, low-GI carbohydrates (slow carbs) are generally your best everyday carb choice (as part of balanced meals and snacks) because they provide steady energy and help keep blood glucose levels stable.
However, if you exercise consistently—especially for longer than an hour—you can and should start including faster-digesting carbs as part of your balanced diet.
Higher-GI carbohydrates (intermediate GI for those with sensitive blood glucose and high GI for healthy persons) can then play a useful role during prolonged exercise or immediately afterwards, when your muscles need to replace the energy they've just used and are more efficient at processing faster carbs.
This is one more reason why the Smart Health Diet doesn't believe in eliminating entire food groups. Instead, it's about understanding when and how different foods work best for your body.
Can you speed up your metabolism?
You've probably heard someone say, "I just have a slow metabolism."
While factors such as age, hormones, body size, and genetics all play a role in how much energy your body uses, one of the biggest factors you can influence is your muscle mass.
✨The more lean muscle you have, the more energy your body naturally uses throughout the day—even while you're sitting at your desk or sleeping.
Exercise also temporarily increases your metabolic rate while your body recovers, and simply eating a balanced diet requires energy to digest and process your food.
Your metabolism isn't set in stone! Many of the daily choices you make have a direct influence on it.
The biggest reward may come years from now
Perhaps the greatest benefit of exercise is one you don't immediately notice.
Regular physical activity significantly lowers your risk of developing many of the lifestyle diseases that become more common as we age, including heart disease, high blood pressure, type 2 diabetes, osteoporosis and certain cancers.
It also helps you to maintain your strength, balance and independence for longer. In other words, staying active today greatly improves your chances of remaining active in ten or twenty years. That's a powerful investment. The oldest (and healthiest) people in the world, who live in the Blue Zones, are all active.
Smart Health's recommendation
Aim to move your body for 30–60 minutes most days of the week. Don't worry about doing it perfectly. Don't worry about whether today's walk was fast enough or long enough.
Just keep showing up. Research has found that many people keep on exercising if they do it with someone - a spouse, friend, child, sibling, etc. The reason for this is that, if the one does not feel like it, chances are good that on that particular day, the other one will feel like it.
Some days you'll feel energetic. Other days you'll only manage a gentle stroll around the block. Both count. Lasting health isn't built by one heroic workout, but through thousands of ordinary decisions to keep moving, one day at a time.
A Quick Word About Smoking
While regular exercise is one of the best things you can do for your health, smoking remains one of the most harmful lifestyle habits.
Smoking damages almost every organ in the body.
It narrows your arteries,
raises blood pressure,
increases the risk of heart disease, stroke, lung disease
and many cancers,
reduces fertility,
slows healing after surgery and
makes exercise far more difficult than it needs to be.
It also affects the health of the people around you through passive smoking.
The encouraging news is that smoking is also one of the most preventable risk factors for chronic disease. If you smoke, deciding to quit is one of the most valuable investments you can make in your long-term health.
Scientific References:
Buettner D (2008): The Blue Zones: lessons for living longer from the people who’ve lived the longest. The National Geographic Society.
Geuegnon C, Mougnin F, Simon-Rigaud ML, et al (2012): Effects of an in-patient treatment program based on regular exercise and a balanced diet on high molecular weight adiponectin, resistin levels and insulin resistance in adolescents with severe obesity. Appl Physiol Nutr Metab, 37(4):672 – 679.
NIH. National Insitute of Health (2003): The seventh report on the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. US Department of Health and Human Services. NIH Publication, 03 – 5233.
Seedat YK and Rayner BL (2012): South African Hypertension Guide 2011. SAMJ, 102(1): 60 – 83.
World Cancer Research Fund, American Institute for Cancer Research (2007): Food, nutrition, physical activity and the prevention of cancer: a Global Perspective. Online, Accessed January 11, 2012.
AUTHOR: ELIZABETH (LIESBET) DELPORT - Registered Dietitian, M.Sc. Dietetics.
Liesbet Delport has over 40 years of experience helping over 10,000 people improve their health through practical, evidence-based nutrition.
After struggling with her own weight as a teenager, Liesbet learned that lasting health isn't about willpower or another restrictive diet. Her approach is simple: people aren't failing, the diets are. She helps people build a balanced, delicious way of eating they can actually follow for life.
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