How to Lose Body Fat While Maintaining Muscle
Updated: Sep 23
ATMS Accredited Member | SIBO-Certified Nutritionist | Microba Certified Nutritionist
Published: 23 September 2026
A practical guide to protein, resistance training and sustainable fat loss from a Clinical Nutritionist in Sydney.
If you go to the gym and want to feel leaner, the goal is usually not simply to weigh less. It is to reduce body fat while maintaining muscle, strength and energy.
Weight loss can include fat, water and muscle. The right nutrition and training plan helps protect the muscle you have worked hard to build.
Ola’s clinical perspective: “Successful fat loss is not about eating as little as possible. It is about creating a manageable calorie deficit while giving your body enough protein, resistance training and recovery to maintain muscle.”— Ola Krawczyk, Clinical Nutritionist and ATMS member
What does “toned” actually mean?
“Toned” usually means:
Having enough muscle to create shape
Carrying less body fat over that muscle
Maintaining good strength and posture
Fat cannot turn into muscle. You reduce fat and build or maintain muscle through two separate processes.
1. Create a moderate calorie deficit
Fat loss requires you to use more energy than you consume, but a very low-calorie diet is not necessarily better.
Too large a deficit may cause:
Constant hunger and cravings
Low energy and poor concentration
Reduced gym performance
Poor sleep and recovery
Greater risk of muscle loss
Menstrual or hormonal changes in some people
For many active adults, eating approximately 10–20% below maintenance calories is a practical starting point. Research also suggests avoiding deficits greater than about 500 calories per day when preserving muscle is a priority. Read the meta-analysis
Example: If someone maintains their weight at around 2,000 calories per day, an initial target may be approximately 1,600–1,800 calories. Calorie calculators are estimates, so adjust the plan according to progress, hunger, training and health.
2. Eat enough protein
Protein supplies amino acids used to maintain and repair muscle. It also helps meals feel satisfying.
For people who regularly perform resistance training, approximately 1.6–2.0 g of protein per kilogram of body weight per day is a useful range during fat loss.
For a 70 kg person, this equals approximately 112–140 g per day.
Spread protein across the day and include a useful source at each meal:
Eggs, chicken, fish or lean meat
Greek yoghurt, cottage cheese or milk
Tofu, tempeh or edamame
Lentils, beans or chickpeas
Protein powder when food is not convenient
A 2022 meta-analysis found small additional lean-mass benefits from higher protein during resistance training, with lower-body strength benefits more apparent from approximately 1.6 g/kg/day. Read the study
3. Continue resistance training
During a calorie deficit, resistance training signals that your muscle is still needed.
Aim to:
Train every major muscle group at least twice per week
Use weights that are challenging with good technique
Gradually increase the weight, repetitions or difficulty
Allow enough recovery between sessions
Include walking or cardio for heart health and fitness
Cardio is helpful, but it should not replace resistance training when maintaining muscle is the goal. Australian movement guidelines
4. Eat protein and carbohydrates around training
Protein and carbohydrates have different roles:
Protein supports muscle repair and maintenance.
Carbohydrates provide training fuel and replenish muscle glycogen.
Before training
Before training, include approximately 20–40 g of protein to provide amino acids for muscle maintenance and repair. These examples focus mainly on protein. You can add some carbohydrate—such as fruit, oats or toast—before a longer or more demanding session if you need additional training fuel.
Try one of these one to three hours before exercise:
Greek yoghurt with chia seeds (chia pudding)
Eggs with cottage cheese and spinach
Chicken, tuna or tofu with a small salad
A protein shake made with milk or soy milk
After training
After training, combine protein with a carbohydrate-rich food. Protein supports muscle repair, while carbohydrate is digested into glucose and helps replenish muscle glycogen.
A meal within approximately two hours is practical. Pure glucose supplements and immediate refuelling are generally unnecessary for recreational gym-goers who train once a day—ordinary carbohydrate foods can provide the glucose needed to restore glycogen. Total daily protein, energy intake and overall diet remain the main priorities. Sports-nutrition position stand
Suitable meals include:
Chicken or tofu with rice and vegetables
Fish with potatoes or sweet potato
Greek yoghurt with banana and oats
A milk-based protein smoothie with banana and berries
5. Build filling meals
A simple fat-loss plate can include:
Protein: approximately one-quarter to one-third of the meal
Vegetables or salad: around half the plate
Carbohydrate: an amount matched to training and energy needs
Healthy fat: olive oil, avocado, nuts, seeds or oily fish
There is no need to eliminate carbohydrates. Choose mostly filling, nutrient-dense sources such as potatoes, sweet potatoes, fruit, legumes and whole grains.
How do leptin and ghrelin affect hunger?
Leptin: the longer-term energy signal
Leptin is produced mainly by fat cells.
It helps signal to the brain that the body has stored energy.
As body fat and calorie intake decrease, leptin may fall.
Lower leptin can contribute to increased hunger and reduced energy expenditure.
Ghrelin: the hunger signal
Ghrelin is produced mainly in the stomach.
It usually rises before meals and falls after eating.
During weight loss, ghrelin may increase and make you feel hungrier.
Protein, fibre-rich foods and regular balanced meals may improve fullness.
These responses are normal biology—not a lack of willpower. A moderate deficit is usually easier to maintain than severe restriction.
Why sleep matters
Poor sleep can increase hunger and cravings, reduce training performance and make recovery harder. Aim for a regular routine and approximately seven to nine hours when possible.
What if you have hypothyroidism or Hashimoto’s?
If hypothyroidism is not adequately managed, it may contribute to fatigue, fluid retention and lower energy expenditure.
Have your thyroid function and medication reviewed before aggressive dieting.
Do not treat a 500-calorie deficit as a target—it is an upper guide.
A smaller deficit may better protect energy, training and muscle.
Can supplements help?
Supplements are optional and cannot replace food or training.
Protein powder: a convenient way to reach your protein target.
BCAAs: usually unnecessary if you already eat enough complete protein. The AIS places them in Group C, where evidence does not support routine use by athletes.
L-carnitine: does not automatically increase fat burning; reviews suggest any average weight-loss effect is small. Read the review
Frequently asked questions
Can I lose fat and gain muscle at the same time?
Yes, particularly if you are new to resistance training, returning after a break or have more body fat to lose. Experienced, lean gym-goers may need to focus on maintaining muscle.
How quickly should I lose weight?
Approximately 0.5–1% of body weight per week is commonly used as a guide, although slower progress may suit leaner people. Evidence-based recommendations
A 12-week or three-month phase can provide enough time to assess progress, but it is not a compulsory minimum.
Is 17–20% body fat the ideal goal?
There is no ideal percentage for everyone. 17–20% may be lean for some men and very lean for many women. It is not required for health or a toned appearance. Pushing body fat too low through under-eating can affect energy, menstrual function, bone health and recovery.
Is a DXA scan useful?
A DXA scan can estimate fat and lean mass, but results can vary with hydration, food intake and testing conditions. If tracking change, use the same facility and similar preparation each time. The AIS advises that body composition is only one of many health and performance factors. AIS guidance
How do I know if my deficit is too large?
Watch for:
Persistent exhaustion or constant hunger
Rapidly declining strength
Poor sleep, irritability or low mood
Menstrual changes
Frequent illness or injury
These signs deserve attention rather than further restriction.
The bottom line
To reduce body fat while maintaining muscle:
Use a modest calorie deficit.
Eat approximately 1.6–2.0 g/kg of protein when appropriate.
Train each major muscle group at least twice weekly.
Include carbohydrates to support training and recovery.
Prioritise sleep and monitor strength, energy and wellbeing.
The best plan is not the one that produces the fastest weight loss. It is one that improves body composition while protecting your muscle, health and relationship with food.
Need a personalised fat-loss and muscle-maintenance plan?
If you go to the gym and want to reduce body fat without sacrificing muscle, I can help you calculate realistic energy and protein targets and turn them into meals that suit your training, health needs and lifestyle.
This article is for education only and does not replace medical advice, diagnosis or individual treatment.
About the Author
Ola Krawczyk is a Clinical Nutritionist and accredited ATMS member providing personalised, evidence-informed nutrition consultations in Sydney and online across Australia.
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