Losing weight isn’t always the goal. At least, not if it comes at the cost of your muscle, strength, or long-term health.
At The Lab, we often talk about the difference between weight loss and fat loss, because they are not the same thing, and what you prioritise matters depending on your goal.
⚖️ What Is Weight Loss?
Weight loss refers to a reduction in total body weight, including:
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Fat
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Muscle
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Water
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Glycogen (stored carbs)
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Even digestive content
This is the number you see on the scales, and it’s easily manipulated day-to-day by hydration, food intake, stress, and sleep.
🔥 What Is Fat Loss?
Fat loss is the targeted reduction of adipose tissue (body fat) while preserving muscle mass. It’s more specific, and far more meaningful in the long term.
If two people lose 5kg:
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Person A loses mostly muscle = flatter, weaker, slower metabolism
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Person B loses mostly fat = leaner, stronger, healthier
We want to be Person B.
💡 Why It Matters: Health, Strength, and Longevity
Muscle isn’t just for aesthetics, it’s critical for:
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🔗 Joint protection and mobility
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🦴 Bone density and fracture prevention
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🧬 Metabolic health and blood sugar control
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🔋 Higher resting energy expenditure (more calories burned at rest)
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💪 Overall resilience as we age
🧠 What the Science Says
✅ Longland et al. (2016)
In a 4-week calorie deficit, the high protein group (2.4g/kg/day) gained muscle and lost more fat compared to the moderate protein group (1.2g/kg/day), who lost some lean mass.
🔍 Takeaway: You can gain muscle and lose fat at the same time with the right nutrition and training.
✅ Morton et al. (2018) - Meta-analysis
Protein intake alongside resistance training significantly increased lean mass and strength, with 1.6g/kg/day being a reliable intake for most.
🔍 Takeaway: Prioritise protein to preserve or build lean tissue during weight loss.
✅ Srikanthan & Karlamangla (2014)
Muscle mass was a stronger predictor of survival than BMI in older adults. Higher muscle = lower all-cause mortality.
🔍 Takeaway: What’s lost or gained matters more than the number on the scale.
It’s also worth noting that excessive cardio, especially when poorly timed or intense, can increase muscle loss during dieting. Learn more in our guide: Does Cardio Affect Muscle Growth?
🛠 How to Prioritise Fat Loss Over Weight Loss
1. Lift Weights
Resistance training is the best insurance policy for keeping muscle while in a calorie deficit. Even 2-3x per week makes a big difference.
For structure and accountability, Small Group Personal Training is a great way to train with purpose and support.
2. Eat Enough Protein
We recommend 1.6-2.2g per kg of bodyweight, more if you're leaner or training harder.
3. Don’t Crash Diet
Rapid drops in calories almost always lead to muscle loss. Start with a moderate deficit (15–20% below maintenance) and track strength over time.
4. Use More Than Just the Scale
We use photos, strength markers, and how clothes fit, not just the number on the scales.
Example: A 70kg client stays the same weight for 3 months but drops 2 clothes sizes and hits new PBs. That’s body recomposition in action.
⚠️ But What If You Do Need to Lose Weight?
In certain cases, particularly where overall mass increases risk of disease or mortality, weight loss is an important health intervention.
But even here, muscle retention is vital:
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You still want to be strong enough to carry your body.
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You still want to move well.
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You still want to be metabolically healthy as you lose.
Muscle is not optional, even during aggressive weight loss.
Eventually, the goal should pivot from just losing weight to maintaining muscle and lowering fat mass sustainably.
👊 Final Thought
Fat loss is the goal.
Muscle is the key.
And the scale? It’s just one tool, not the final verdict.
If you’re new to training or unsure where to begin, remember: you don’t need to be fit to start, you just need to start.
References
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Longland TM et al. (2016). Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss. The American Journal of Clinical Nutrition.
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Morton RW et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine.
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Srikanthan P, Karlamangla AS. (2014). Muscle mass index as a predictor of longevity in older adults. The American Journal of Medicine.
