Weight Loss Drugs: How They Work, Benefits, Risks & What to Consider.

Weight loss medications continue to try and change the conversation around weight management. The current era of weight loss medications, including semaglutide (aka Ozempic and Wegovy) and tirzepatide (aka Mounjaro) have made it significantly easier for some people to reduce their food intake and lose weight. For others, they may not be appropriate, well tolerated or necessary.

At Dig In Health Co, we believe the conversation shouldn't stop at the number on the scales, in fact it shouldn’t even start there, and that’s because the true picture of health is more nuanced than simply “losing weight”. If a medication is helping you eat less, what you eat becomes that much more important. Adequate protein, vitamins, minerals, fibre and overall dietary quality help support muscle and bone health, immune and energy systems; gut and mental health; ensuring long-term wellbeing while weight is changing. So, how do these medications work, who might benefit from them, and what should you be thinking

about nutritionally?

How Do These New Weight Loss Medications Work?

There are several types of prescription weight loss medications, but the medications receiving the most attention currently are the GLP-1 and GIP/GLP-1 medications.

In Australia, medicines in this group include semaglutide, liraglutide and tirzepatide. Some are approved for type 2 diabetes, while others are approved for chronic weight management. These medications work partly by influencing the hormones and brain pathways involved in hunger, appetite and fullness. For example, GLP-1-based medications can:

• Reduce appetite

• Increase feelings of fullness

• Slow gastric emptying, meaning food moves more slowly through the stomach

• Reduce cravings and the drive to eat

• Ultimately reducing overall energy intake.

  
  

Tirzepatide acts on both GIP and GLP-1 pathways. In simple terms, the medication can make it easier to eat less without feeling like you are constantly fighting hunger.

This reduction in total calorie intake is an important part of why these medications can be effective for weight loss. But eating less does not automatically mean eating well.

When appetite is significantly reduced, it is possible to consume fewer calories while also consuming less protein, fibre, iron, calcium and other essential nutrients. Emerging research is highlighting the importance of proactive nutritional support during GLP-1-based treatment.

Why are Weight Loss Medications Suitable for Some People and Not Others?

Weight loss medication isn't a one-size-fits-all solution. For some people living with excess weight or obesity, medication can be an effective part of a broader treatment plan. For example, Wegovy is approved in Australia for chronic weight management in adults with obesity, or overweight alongside at least one weight-related health condition. Your doctor will consider factors such as your health history, other medications, potential side effects, treatment goals and whether the medication is appropriate for you. One potential benefit: less "food noise". One of the experiences people commonly describe when taking appetite-regulating medications is a reduction in persistent thoughts about food.

You might previously have experienced:

"What am I going to eat next"

"I've already eaten, but I still want something sweet"

"I'm stressed, so I feel like eating"

"I can't stop thinking about food"

When appetite and cravings become quieter, some people find it easier to distinguish physical hunger from habits, cravings or emotionally driven eating.

This can be particularly useful for people who have spent years feeling that they are constantly battling their appetite. However, medication doesn't necessarily address the underlying reasons someone eats. Stress, emotional eating, boredom, poor sleep, restrictive dieting and learned eating patterns can all still exist. Nutrition and behavioural support can therefore be valuable alongside medication

What are the Common Side Effects?

The most common side effects of GLP-1 and related medications involve the gastrointestinal system. These can include:

• Nausea

• Vomiting

• Constipation

• Diarrhoea

• Bloating

• Abdominal discomfort

• Reflux.

These effects are partly related to changes in appetite and gastric emptying.

For some people, these symptoms settle as their body adjusts. For others, they can significantly affect how much and what they are able to eat. This is where nutrition support can make a real difference. Rather than simply telling someone to "eat less", a dietitian can help you work out how to get enough nutrition into a smaller appetite, while also finding foods and meal patterns that are easier to tolerate.

What About the Long-Term Risks?

Weight loss medications are still a relatively new area of treatment, and our understanding of their very long-term effects continues to develop. This doesn't mean they are unsafe. It means that, like any long-term medication, their benefits and risks need to be considered individually and monitored over time. There are established and emerging safety considerations that your doctor should discuss with you. These can vary depending on the specific medication. For GLP-1-based medications, there are important considerations around potential gastrointestinal symptoms, gallbladder and pancreatic problems, kidney problems associated with significant dehydration and delayed gastric emptying.

There are also newer safety warnings. In 2025, the TGA added warnings about aspiration during general anaesthesia or deep sedation because these medications can delay gastric emptying. If you are taking one of these medications, it is important to tell your doctor, anaesthetist or other relevant health professional before a procedure.

In July 2026, the TGA also updated warnings regarding a rare but serious eye condition called non- arteritic anterior ischaemic optic neuropathy (NAION), which can cause permanent visual impairment. The evidence and risk appear to differ between individual medicines, so this is something to discuss with your treating doctor rather than assuming it applies equally to every person or medication. There is also an important nutrition consideration that is often overlooked:

Losing weight isn't the same as losing only body fat. When people lose weight, some of the weight lost can come from lean mass as well as fat. The landmark STEP 1 trial for semaglutide (Wegovy/Ozempic) determined that approximately 38% to 39% of the total weight lost by participants came from lean soft tissue (often referred to broadly as lean mass, which includes skeletal muscle), while the remaining 61% to 62% came from fat mass. Emerging research suggests that preserving muscle during significant weight loss should be prioritised as part of treatment. Adequate protein and resistance exercises are two essential strategies.

This is one reason we strongly believe the scales should not be the sole measure of success.

Nutrition Matters More, Not Less

Perhaps the biggest misconception about weight loss medication is: "If the medication is doing the work, I don't need to worry about my diet" Actually, the opposite is true.

If your appetite drops substantially, you may have much less food to work with each day. This means every meal and snack has an opportunity to provide useful nutrition.

Think nutrient density, not just calorie reduction. Rather than asking:

"How little can I eat? We want to ask: "How can I make the food I am eating count?"

Research is increasingly highlighting potential concerns around inadequate protein and

micronutrient intake during GLP-1-based therapy, particularly when food intake becomes very low.

Protein is essential. The hidden risk: losing muscle mass

Protein deserves particular attention during weight-loss. When energy intake is reduced, adequate protein can help support the maintenance of lean mass, including muscle. This is particularly important when weight is being lost relatively quickly. One of the less discussed considerations with weight loss medication is what type of weight is being lost?.

When body weight decreases, the loss is not exclusively body fat. Some lean mass — including muscle — can also be lost. This can become a greater concern when appetite is significantly suppressed and a person is consistently eating too little protein, too few calories or a diet lacking in essential nutrients.

Why Does This Matter?

Muscle isn't just about strength or appearance. It plays an important role in mobility, metabolic health, hormone and immune health, physical function and healthy ageing.

Significant loss of muscle mass over time can contribute to:

• Reduced strength and physical function, making everyday activities such as lifting, climbing stairs or getting up from a chair more difficult.

• Reduced exercise capacity, which can make it harder to stay active and maintain fitness.

• A lower metabolic rate, because muscle tissue contributes to energy expenditure. This can make maintaining weight and body composition more challenging over time.

• Greater risk of frailty as we age, particularly when muscle loss is combined with reduced physical activity.

• Poorer recovery from illness, injury or surgery, as adequate muscle and nutritional reserves are important during periods of physical stress.

• Reduced bone and musculoskeletal health, particularly when muscle loss occurs alongside inadequate calcium, vitamin D, protein and resistance exercise.

• Loss of independence later in life, when maintaining strength and physical function becomes increasingly important.

This is why the goal of weight management shouldn't simply be to "lose as much weight as possible" A better goal is to reduce excess body fat while protecting muscle, strength and nutritional status.

How Can You Protect Your Muscle?

There are three important pieces of the puzzle:

1. Eat enough protein. Protein provides the amino acids your body needs to maintain and repair muscle tissue. When you're eating less overall, making protein a priority becomes particularly important.

2. Include resistance training. Walking and cardiovascular exercise are valuable for overall health, but resistance training provides an important stimulus for your muscles to maintain their size and strength during weight loss. This might include weights, resistance bands, bodyweight exercises or appropriately prescribed strength training.

3. Prioritise nutritional quality. Protein is only one part of the picture. If your overall food intake becomes very low, you may also be getting less iron, calcium, magnesium, zinc, vitamin B12, folate, vitamin D and other essential nutrients.

This is where working with a dietitian can be particularly valuable. Rather than simply trying to eat as little as possible, the focus becomes:

How do we make the food you are able to eat as nutritionally valuable as possible?

For someone taking weight loss medication, this may mean adjusting meal size and frequency, choosing protein-rich foods first, using nutrient-dense snacks or drinks when appropriate, and finding strategies to manage nausea, early fullness or other gastrointestinal side effects.

Good protein sources include:

• Chicken and lean meats

• Fish and seafood

• Eggs

• Milk, yoghurt and cheese

• For vegetarians and vegans: tofu, tempeh, legumes and lentils should be prioritised and protein-enriched foods or supplements where appropriate.

  
  

Rather than leaving protein until dinner, you should include sources of protein at every meal

throughout the day. For example:

Breakfast: Greek yoghurt, berries and nuts (+/- a suitable protein powder, as required)

Lunch: Chicken, tofu or lentil salad

Snack: Cottage cheese, boiled eggs or a protein-rich smoothie

Dinner: Fish, lean meat, tofu or legumes with vegetables

Your individual protein requirements will depend on factors including body size, age, activity levels, health conditions and your overall diet. A dietitian can help determine an appropriate target for you.

Don't Forget the Minerals

When you're eating substantially less food, you can unintentionally eat substantially less of the foods that provide essential micronutrients. This can include nutrients such as:

• Iron

• Calcium

• Magnesium

• Zinc

• Potassium

• Vitamin B12

• Folate

• Vitamin D.

  
  

Some emerging research has identified inadequate micronutrient intake among people using GLP-1- based therapies, although more research is needed to understand the extent to which medication itself contributes to these deficiencies. This is why food quality matters.

A small meal of highly processed food may provide relatively little protein, fibre or micronutrients. A smaller meal containing animal-based protein, vegetables and healthy fats can provide considerably more nutritional value.

Fibre and Fluids Matter

Constipation can be a common side effect, so maintaining adequate fluid and fibre intake can be helpful where tolerated. Good fibre sources include vegetables, fruit, legumes, wholegrains, nuts and seeds. However, if you are experiencing significant nausea, bloating or early fullness, suddenly increasing fibre may make symptoms worse. Nutrition strategies should therefore be individualised rather than following a rigid checklist.

The Bigger Picture

Weight loss medication can be an effective tool, but the number on the scales doesn't tell the whole story. Two people could lose the same amount of weight while having very different changes in body fat, muscle mass, strength and nutritional status.

At Dig In Health Co, we want to look beyond weight alone. Our goal is to help you lose weight in a way that supports muscle, strength, nutrition, energy and long-term health — because maintaining your health is about much more than achieving a particular

number on the scales. If appetite is reduced, nutrition needs to become more intentional — not less. Our focus is not simply helping you eat fewer calories. It is helping you make those calories nutritious, satisfying and supportive of your long-term health.

That means thinking about:

Protein → muscle and lean mass

Fibre → gut health and bowel regularity

Micronutrients → vitamins, minerals and overall health

Food quality → making a smaller amount of food more nutritious

Resistance training → supporting strength and muscle

Hydration → particularly when gastrointestinal side effects are present.

And perhaps most importantly, building eating habits that support you whether you are taking

medication now, reducing your dose in the future, or eventually coming off it.

Weight loss is one outcome. Health, strength and quality of life are the bigger picture!

Let’s Work Together

Talk to us before you start, or at any stage of your treatment. Our dietitians can help you understand how changes in appetite and food intake may affect your nutritional needs, while working alongside your GP or prescribing health professional to support your health and wellbeing. You can learn more or book an appointment at:

www.diginhealthco.com.au