Understanding Weight-Loss Medications: What You Need to Know

By Dallas Demeny, Accredited Pactising Dietitian, MND, BSc, Grad Dip Ed.

When a new weight-loss treatment hits the news, it’s natural to jump online and look for answers. But the information out there can be overwhelming, and sometimes misleading. Hopefully the following information will help you understand how weight-loss medications fit into your overall health journey.

Weight-Loss Medications Are Just One Part of the Picture

Weight-loss medications can be a helpful tool, but they work best when combined with:

· Healthy eating (with support from a dietitian)

· Regular physical activity (often guided by an exercise physiologist)

· Positive lifestyle habits

· Support from your GP and broader healthcare team

Think of medication as one tool in a larger toolbox; not a complete solution on its own.

How These Medications Work

Some prescription medications can be used long term and may help you lose more weight than lifestyle changes alone. They work in different ways, such as:

· Helping you feel less hungry

· Helping you feel full sooner

· Reducing how much fat your body absorbs

However, they do not replace healthy habits—they work best alongside a supportive lifestyle plan.

Side Effects and Safety

Most people experience mild side effects when they start treatment, like:

· Nausea

· Constipation

· Loose stools

These usually improve over time. Serious side effects are rare, but it’s important to discuss what to expect with your GP and know when to seek help.

Nutrition Still Matters.. A Lot

Because these medications can significantly reduce appetite, which may help with weight loss, it also means there’s a risk of:

· Not getting enough essential nutrients

· Missing key vitamins and minerals

· Losing muscle mass instead of fat

A drop in body weight doesn’t automatically mean a person is well nourished. There are already case reports of thiamine (vitamin B1) deficiency and protein malnutrition in people using certain weight-loss medications. This is why nutrition support is essential, especially when you’re eating less. What you eat matters even more.

There’s still a lot we don’t know about:

· How these medications change eating patterns

· Whether nutrient intakes remain adequate

· Whether long-term use supports overall wellbeing, not just weight loss

Your dietitian plays a key role in helping you stay well nourished throughout treatment.

What Happens When You Stop the Medication?

It’s common to regain some weight after stopping. This doesn’t mean you’ve failed, it’s a known pattern linked to how the medications work. Maintaining balanced meals, regular movement, and other healthy habits can help reduce weight regain.

Your healthcare professional may recommend continuing the medication if it’s helping you:

· Lose weight safely

· Manage health risks

· Improve overall wellbeing

If it hasn’t helped you lose at least 5% of your body weight within 3–6 months, your GP may suggest a different approach.

BMI. A Useful Tool, But Not the Whole Story

Doctors often use Body Mass Index (BMI) to understand weight-related health risks. While BMI gives a general guide, it doesn’t tell the full story. Other factors—such as age, muscle mass, medical history, and lifestyle—are also important. Medication may be recommended if lifestyle changes alone haven’t been enough to reach your goals.

Cost and Access

Weight-loss medications can be expensive. In Australia, some may be supported by Medicare or covered by private health insurance—but not all. It’s worth checking with your GP, pharmacist, or insurer before starting.

The Bottom Line

Weight-loss medications can be effective, but they are not a standalone solution. They work best when combined with healthy habits and guidance from your healthcare team. Your GP, dietitian, and exercise physiologist can work with you to find the right mix of treatments and support to help you reach your health goals safely.

If you’re considering weight-loss medication, start by having a conversation with your GP; they can help you make an informed, personalised decision and refer you to the rest of your healthcare team.

Dallas Demeny is an Accredited Practising Dietitian (APD) with a rich and varied background spanning molecular biology, education, and clinical nutrition. She began her career as a research scientist, investigating the cell-to-cell transfer of genetic material in gut bacteria; an experience that laid a strong scientific foundation for her future pursuits.

Driven by a passion for knowledge and communication, Dallas spent 16 years teaching high school Science and Mathematics. Her professional journey has been shaped by diverse experiences, including international travel, raising a family, and embracing a range of roles that reflect her adaptability and curiosity.