Dr Karen L Hartzenberg

19/11/2025

Why did this young athlete faint during training?
Meet Alex, a 16-year-old triathlete training hard for national championships. He was talented, driven, and clocking hours of swimming, cycling, and running every week.
One day, during a routine session, Alex felt faint, developed pins and needles in his arms and legs, and became weak and shaky. He was rushed to the emergency department and diagnosed with dehydration.
💡 But was it just dehydration?
When I assessed Alex, the real issue became clear:
⚡ He wasn’t eating enough to fuel his training or his growing body.
🚨 What is RED-S?
Relative Energy Deficiency in Sport (RED-S) happens when athletes burn more energy than they consume, leaving too little for basic body functions.
In teenagers, this can cause:
📉 Fatigue & dizziness
🦴 Weaker bones (stress fractures risk)
💪 Slow recovery & poor performance
🩸 Hormonal changes (even in males!)
😷 Lower immunity

🍫 Alex’s Diet (Before)
🥤 Juice + toast for breakfast
🍫 Energy bar + sports drink at school
🥪 Sandwich + crisps + jelly babies
🥤 Pre/post-training shakes
🍗 Rice + chicken + salad for dinner
🍦 Ice cream before bed
Sounds okay? Not for a young athlete burning thousands of calories daily.

✅ The Fix
We rebuilt Alex’s diet with:
🍳 Balanced, hearty breakfasts
🍌 Nutrient-dense snacks (yogurt, nuts, trail mix)
🍗 Bigger protein portions
🥛 More whole foods rich in iron, calcium, zinc & vitamin D
🥣 Bedtime snacks to prevent overnight deficits

✨ 8 Weeks Later
✅ 2.5kg lean mass gained
✅ No more dizzy spells or shakiness
✅ Faster recovery & improved endurance
✅ “Night-and-day” difference reported by his coach

📝 Takeaway for Young Athletes
You can’t out-train poor nutrition.
✔️ Under-fuelling isn’t discipline... It sabotages performance and health.
✔️ Teens need more energy to grow, train, and recover.
💡 Your nutrition is your secret weapon.
👉 Read Alex’s full story & the science of RED-S here: https://lifestyledoc.co.za/case-study-the-hidden-risks-of-under-fuelling-in-young-athletes/

17/11/2025

Do you know what a 'Healthy Plate' is?

A healthy plate contains all the important nutrients your body needs to thrive. If you can achieve a 'Healthy Plate' for most of your meals... not only will you lose weight, but you will feel fantastic too.

The first step to achieving a 'Healthy Plate' is to add more fresh vegetables at each meal. Try and cover 50% of your plate with veggies and you will be well on your way to having a 'Healthy Plate' and feeling great!.

Next, make sure you get enough protein. About 25% of what you eat each day should be protein. Fish, chicken, eggs, meat and dairy products are high in protein and good sources of vitamin B12. Plant-based proteins like tofu, edamame beans, lentils, dried beans and pulses, and quinoa are rich in minerals and healthy fibre.

Also, be sure to include some healthy fats: Olive oil, nuts and seeds, avocado, coconut and dark chocolate are all great sources of fat that keep you feeling fuller for longer and help you absorb certain vitamins (like vitamin A, D, K and E).

Learn more about healthy eating on my Nutrition Basics Online Course and take advantage of the Black Friday special and get a 50% discount: https://www.udemy.com/course/health-and-vitality-bootcamp-nutrition-basics/?couponCode=BLACKFRIDAY

07/11/2025

Thank you to everyone who attended our Mega Zumba event to support Link to Life. Your energy was electric. Your moves were awesome. Your joy lit up the field at LSC.

Thank you to our generous sponsors and collaborators... without your support, the event would not have been possible.

Thank you to Link to Life for the amazing work you do to support people living with cancer in Mauritius.

Looking forward to seeing you all again soon on the dancefloor!

01/11/2025

I am simply delighted to share with you my new programme, Nutrition Basics PLUS! Over 90 days, in this series, we will journey through my Udemy Nutrition Basics course (you can view the course here) and I will provide additional guidance and resources directly into your inbox to encourage and educate you.

The Udemy course is divided into 8 sections designed to help you understand the nutritional needs of your body better so you can be confident in making good food choices. Transform your health, control your weight, and enjoy delicious food.

You will:
*discover how your body uses carbohydrates, proteins, fats, vitamins and minerals.
*learn that carbohydrates are NOT essential nutrients and that alcohol is a FOOD GROUP for a number of reasons.
*discover that drinking 8 glasses of water a day might not be necessary (and you will *learn that there's a better way to gauge your level of hydration).
understand why counting calories is a waste of time and mental energy.

You can work through the course at your own pace but as some of the sections are quite intense, each week I will share what content I think you should watch. Breaking it down into digestible portions will allow you to absorb it and put it into action.

Alongside the course, you will receive:
*downloadable resources such as recipes and guides.
*complementary videos digging deeper into vitamins, minerals, different diets, how to meal plan and shop as well as hot topics like snacking and calorie counting.
*case study videos sharing how optimising nutrition helps you with real-world examples.

Together, over 90 days, we will improve your health, vitality, energy and longevity through optimal nutrition! At the end, you will be empowered with skills that will allow you to emerge victorious from the grocery store, without being conned into buying unhealthy foods by stealthy food packaging.

And, your meals will be more balanced, healthy and nutrient-dense which means that you and your family will enjoy better health, improved energy and vitality.

While this is scheduled as a 90-day series, you can work at your own pace and will have lifetime access to all the content you receive as well as the Udemy course.

I really love feedback and questions so you will be able to email me at any time as well as join a private Facebook group.

You receive all of this for launch price of only $15. Are you ready? Let’s go!

Purchase and join here: https://lifestyledoc.co.za/product/nutrition-basics-plus/

31/10/2025

💊 When Medicines Multiply…

Garth was in his 60s when he came to see me. Once a promising rugby player, a knee injury left him with chronic pain. To cope, he was put on anti-inflammatories.
➡️ They caused a stomach ulcer → so he was given an acid-blocker.
➡️ He gained weight and developed high blood pressure → so he was given amlodipine.
➡️ Amlodipine caused swollen feet → so he was given a diuretic.
➡️ The diuretic raised uric acid, blood sugar & cholesterol → so he was given three more pills.
➡️ Fatigue, depression & erectile problems followed → so he was given two more medicines.
By the time I met him, Garth was taking 12+ daily prescription medications (plus supplements) and still felt awful.

Instead of adding another prescription, we went back to basics:
🥗 A low-carb Mediterranean-style diet.
🏋️‍♂️ Strength training for muscle and joint support.
⚖️ Weight loss and inflammation control.
Step by step, we de-prescribed: blood pressure meds, diabetes pills, statins, NSAIDs, antidepressants, and more. With each one gone, a side effect disappeared.
✨ Garth lost 20kg, his energy and mood returned, and he regained his health, without a pillbox running his life.
👉 The lesson? Sometimes the most powerful medicine isn’t more medication. It’s addressing the root cause, giving patients back control of their health.

Watch and read more here: https://lifestyledoc.co.za/when-medicines-multiply-garths-story-of-polypharmacy-and-the-power-of-de-prescribing/

When most people think of medicine, they imagine it as the answer to their health problems. And often it is, especially in emergencies. But in chronic illness, the story can look very different. Too often, one prescription leads to another, then another, until the very medicines meant to help become...

30/10/2025

My passion for health and living well continues to drive what I do so I have created a new product, and I’m excited to share it with you!

I am looking to gently guide you to make a sustainable change to achieve your long-term goal of improved well-being and vitality. I will break it down into digestible portions to allow you to absorb it and put it into action. And then maintain it.

The launch is only 2 days away, watch out on Saturday, 1 November for more information on how to get so much more PLUS take advantage of the special launch price!

18/10/2025

Counting down... Don't miss the dance party of the year!

Join us on Tuesday 28th October 2025 for 90 minutes of great music, fun moves and positive vibes.

In celebration of life. And, in support of .

Starts at 18h00. Rs 200 per person. All proceeds go to Link to Life.

See you there :)

16/10/2025

Intermittent fasting is a powerful way to improve your health and vitality, but you really must do it right to get the benefits.

The first step is to understand how fasting works at a metabolic level! In my Udemy course, you will receive digestible information which you can apply to your life. It includes videos and downloadable resources as well as delicious and easy recipes to try at home.

As you apply the principles of intermittent fasting you can:
· Reduce inflammation
· Gain control of your appetite and your weight
· Manage health conditions like diabetes and IBS
· Improve your energy levels
· Optimize gut health
· Enjoy mental clarity and banish brain fog
· Activate anti-cancer and anti-ageing pathways

Transformation doesn't happen overnight but if you can be a little better today than you were yesterday, and if you can be a little better every day while you are on this journey, you are going to be a whole lot better than when you started!

I'm so delighted to have this opportunity to share my passion for health and living well with you. Lifestyle medicine is a specialized field of medicine, we look at all of these lifestyle related factors that can impact your health and aim to optimize those so that you live a healthier and happier life without the horrible complications of poor lifestyle choices.

The Udemy course is available as a once-off, lifetime access $99 purchase here:
https://www.udemy.com/course/fasting-for-vitality/?referralCode=86027812FF4F9458EEFA