So You Want to Lose 20KG? Here’s How I Would Do It. Part 4 of 4
A Clinical Nutrition Guide to Fat Loss, Muscle Maintenance
Part 4: Putting It All Together
In Part 1, we established the foundations. We stopped treating losing 20 kg as a race and instead defined the objective as reducing excess body fat while preserving skeletal muscle, strength and physical function. We established baseline measurements, estimated energy requirements and created a realistic initial intervention.
In Part 2, we applied the fundamentals. We built the calorie deficit around sufficient protein, carbohydrates, dietary fats, fibre, fruit, vegetables and nutrient-dense foods. We used resistance training to support muscle retention, daily activity to support energy expenditure and dietary structure to make the deficit easier to sustain.
Then, in Part 3, we introduced regressive analysis. Instead of automatically cutting calories when progress slowed, we learned to interrogate the data: weight trends, waist circumference, adherence, activity, training performance, recovery and changing energy requirements. Only when the evidence justified an adjustment did we make one.
Now we need to put everything together.
Because losing 20 kg was never really the end goal.
The goal was to lose the excess body fat, preserve as much muscle and physical function as reasonably possible, improve health—and then build a lifestyle capable of maintaining those improvements.
That final part matters.
A diet that successfully gets you to your target weight but provides absolutely no strategy for what happens afterwards has only solved half the problem.
Stop Thinking of This as One Diet
Looking back across this series, one of the most important principles is that I wouldn't approach losing 20 kg as one continuous, unchanging prescription.
I'd treat it as a series of phases.
magine starting at 110 kg with an eventual target somewhere around 90 kg.
Rather than psychologically staring at that entire 20 kg difference, I'd divide the process into meaningful checkpoints.
110 kg → approximately 105 kg → reassess.
105 kg → approximately 100 kg → reassess.
100 kg → approximately 95 kg → reassess.
95 kg → approximately 90 kg → reassess.
These aren't magical physiological thresholds.
They're decision points.
At each one, I'm asking whether the intervention that brought us here remains appropriate for the person standing in front of me now.
Because the person at 90 kg isn't metabolically identical to the person who started at 110 kg.
Their body mass has changed.
Their energy requirements may have changed.
Their relationship with food may have changed.
Their fitness may have improved.
Their strength may have changed.
Their activity levels may have changed.And hopefully their understanding of nutrition has changed considerably.
The intervention evolves with the individual.
What Are We Measuring Along the Way?
The bathroom scales remain useful.But they never become the only outcome.Throughout the process I'd continue monitoring several variables together.
Body weight gives us one measurement.Waist circumference gives us another.Progress photographs provide visual information.
Training performance gives us some indication of how well physical capacity is being maintained.
Food records tell us whether the nutritional intervention is being executed.
Daily activity tells us whether movement has changed.And the individual tells us about hunger, energy, sleep, recovery and how difficult the programme has become to maintain.
None of these measurements is perfect.
Together, however, they provide a considerably better picture than:“The scales didn't move this week.”
This is where the approach we've built across the four articles becomes important.We're not chasing numbers independently.
We're looking for convergence between multiple pieces of information.
The Full Fat-Loss Framework
If I condensed this entire series into one clinical pathway, it would look something like this:
Assess → Plan → Intervene → Measure → Analyse → Adjust → Repeat → Maintain.
Notice what's missing,
Punishment, Panic, Constant restriction, Diet hopping.
The intervention begins with an assessment.From that assessment we establish approximate energy requirements, nutritional priorities, resistance training and activity.We implement the intervention.Then we measure the response.
If the response is appropriate, we continue.If it isn't, we analyse why.Only then do we adjust.Then the cycle begins again.That is a very different approach from continually asking:“What else can I remove from my diet?”
What Happens as You Get Lighter?
This is something people frequently misunderstand.As body weight decreases, the energy required to maintain that body generally decreases too.Part of this is simple physics.A smaller body requires less energy to move around.There may also be changes in resting energy expenditure, spontaneous physical activity and other components of total energy expenditure.
This means the calorie deficit that existed at 110 kg may gradually become smaller as body mass falls.That's expected.It doesn't mean your metabolism has been “damaged”.It doesn't mean starvation mode has suddenly overridden energy balance.It means the energy equation has changed because the body has changed.
This is exactly why Part 3 was so important.When progress slows, we don't automatically cut calories.We determine whether energy requirements have changed, activity has fallen, adherence has drifted or we're simply observing normal fluctuations in body weight.Then we make the smallest effective adjustment.
Muscle Preservation Remains Non-Negotiable
Twenty kilograms into a weight-loss journey, I don't suddenly stop caring about skeletal muscle because we've reached the target.If anything, this is when protecting what we've retained becomes even more important.
Resistance training continues.
Adequate protein continues.
Recovery continues.
Physical activity continues.
The goal was never simply to produce a smaller body.It was to improve body composition.Imagine two people who both lose 20 kg.One loses substantial body fat but retains most of their muscle and strength.The other loses considerably more lean tissue, becomes weaker and finishes the diet with poor physical capacity.
The scales may display exactly the same result.Physiologically, those outcomes aren't equivalent.This is why the resistance-training programme shouldn't disappear simply because the calorie deficit is ending.
Strength isn't something we temporarily borrow while dieting.It's something we continue building afterwards.
You've Lost 20KG. Now What?
This is where many diets effectively finish.Congratulations.
Target reached.
Before and after photograph.
Diet over.
Except physiologically, nothing magical happened when the scales crossed that final number.You now have a new problem to solve:How do we maintain this substantially lower body weight?
The answer isn't remaining in a calorie deficit forever.At some point, energy intake needs to transition towards the amount required to maintain the new body weight.This doesn't necessarily require an elaborate months-long “reverse diet”.The important objective is simply to move from intentional energy restriction towards an intake that approximately matches current energy expenditure while monitoring the response.
That maintenance requirement may be different from the calories you were consuming before losing weight.And that's where expectations become important.You can't necessarily return to every previous dietary behaviour and expect the new body weight to remain unchanged.
The lifestyle that maintains the new body may need to look different from the lifestyle that existed before the intervention.
Maintenance Is a Phase of Treatment
I think this is one of the most important concepts in the entire series.
Maintenance isn't what happens after the programme.
Maintenance is part of the programme.After a substantial period of energy restriction, I'd deliberately enter a maintenance phase.
Calories increase towards estimated maintenance requirements.
Protein remains adequate.
Resistance training continues.
Activity continues.
Fruit, vegetables and fibre don't disappear.The meal structures developed during the diet remain useful.Body weight continues to be monitored.
The difference is that we're no longer intentionally trying to make it fall.We're learning how to stabilise it.
That requires a different mindset.During fat loss, success might have meant seeing the average trend gradually moving down.
During maintenance, success means seeing that trend remain relatively stable.
The absence of further weight loss is now the objective.
Expect Your Weight to Move
Reaching 90 kg doesn't mean waking up at precisely 90.0 kg every morning for the rest of your life.
Body weight fluctuates.
Water changes.
Glycogen changes.
Sodium changes.
Food volume changes.
Training changes.
Travel happens.
Christmas happens.
Life happens.
So rather than trying to defend one exact number, I'd establish an acceptable maintenance range.For example, somebody finishing around 90 kg might establish a personal range around that weight and monitor the longer-term trend.The precise boundaries should be individualised.The principle is more important:
Don't wait until 10 or 15 kg has returned before responding.
Small deviations are considerably easier to manage than large ones.
Weight Regain Isn't a Moral Failure
This matters because maintenance is rarely perfectly linear.Perhaps you've maintained successfully for eight months.
Then work becomes stressful. Training drops. Steps fall. Meals become less structured. Body weight increases by several kilograms.
The worst response is often:
“I've failed, so what's the point?”
That's all-or-nothing thinking.Instead, return to the same clinical process we've used throughout the series.Assess.
What changed? Was it calorie intake? Alcohol?Activity? Training? Sleep? Meal structure? A change in working circumstances? We don't need guilt.
We need information.
Then we intervene appropriately.This is exactly the same principle we used during the original fat-loss phase:
Data before judgement.
Don't Maintain the Diet. Maintain the Behaviours.
There's an important distinction here.I don't want somebody finishing a substantial fat-loss phase believing they need to remain “on a diet” indefinitely.
But I absolutely want them maintaining many of the behaviours they developed.
Resistance training.
Daily movement.
Adequate protein.
Fruit and vegetables.
Fibre.
Appropriate portions. Some awareness of energy intake. Regular body-weight monitoring. Managing alcohol. Recognising high-energy foods. Having a strategy for restaurants, holidays and social occasions.
Those behaviours aren't temporary dieting techniques.They're simply components of long-term weight management and good nutrition. The calories may change. The objective may change.
The fundamentals don't suddenly become irrelevant.
The Diet Needs to Become Less Visible
One of the signs of successful long-term behaviour change is that eventually the process should require less conscious effort. At the beginning,
you may need to weigh food.
Track calories.
Plan meals.
Read labels.
Monitor protein.
Record body weight.
Those tools can be extremely useful because they teach portion awareness and nutritional literacy.But the ultimate objective isn't necessarily to spend the rest of your life entering every gram of food into an app.
Over time, many people can develop repeatable meal structures, understand appropriate portions and recognise which foods need greater attention.
The intervention gradually becomes less about following a diet and more about having a nutritional system.
That's a much more sustainable destination.
What About Holidays, Christmas and Restaurants?
You live your life.That's the answer.
Long-term weight management cannot depend upon avoiding every environment in which calorie intake might temporarily increase.A week on holiday doesn't invalidate months of good nutrition.
Christmas dinner isn't a metabolic emergency.
A restaurant meal doesn't require two hours of cardio the following morning.
What matters is what happens next.
Return to your normal dietary structure.Return to training.Return to normal activity.
Return to normal portions.
Don't attempt to compensate for one high-calorie day with an extreme period of restriction.
The ability to return to baseline quickly is arguably one of the most valuable skills in long-term weight management.
Don't Confuse Maintenance With Perfection
Someone can maintain a healthy dietary pattern and still eat cake.
They can eat pizza.
They can drink alcohol occasionally.
They can have a takeaway.
The objective isn't to eliminate every food that contributed calories during the original weight gain.It's to understand frequency, portion size and context.If 80–90% of someone's habitual diet provides adequate protein, fruit, vegetables, fibre, micronutrients and appropriate energy intake, there is considerable room for flexibility.
That's important because the diet we're constructing isn't intended to last twelve weeks.
It's intended to inform how someone eats for decades.
Health Is Now Bigger Than the Scales
At the beginning of this series, losing 20 kg was the obvious headline.
By the end, I want the focus to have expanded.
What happened to waist circumference?
What happened to blood pressure?
What happened to physical fitness?
What happened to strength?
What happened to mobility?
What happened to sleep?
If relevant, what happened to glucose regulation and blood lipids?
What happened to someone's confidence in managing their own nutrition?
Body weight matters.But successful weight management should ultimately contribute to a broader improvement in health and physical capability.
That was the point from the beginning.
The Complete Decision Framework
If you remember nothing else from these four articles, remember this:
Establish the baseline.
Understand the person before prescribing the intervention.
Create the deficit.
Use enough energy restriction to produce meaningful progress without automatically chasing the largest possible deficit.
Protect muscle.
Prioritise sufficient protein and progressive resistance training.
Build nutritional quality around the deficit.
Fruit, vegetables, fibre-rich carbohydrates, appropriate dietary fats and nutrient-dense protein sources.
Maintain activity.
Use walking, daily movement and cardiovascular exercise intelligently rather than attempting to exercise away a poor diet.
Measure the response.
Use body-weight trends, waist circumference, training performance and other appropriate outcomes.
Analyse before adjusting.
When progress slows, determine why before changing calories.
Make the smallest effective intervention.
Don't change five variables when one will do.
Repeat the process.
The prescription evolves as the body changes.
Reach the target.
Then change the objective.
Move from loss to maintenance.
And continue monitoring sufficiently to identify meaningful regain before it becomes substantial.
That's the whole system.
Not particularly glamorous.
But that's often what good nutrition looks like.
Practical Takeaways From Part 4
Treat the 20 kg target as several smaller phases.
Reassess periodically rather than assuming the original prescription remains appropriate indefinitely.
Use multiple measures of progress.
Body weight matters, but so do waist circumference, physical performance, adherence and health markers where appropriate.
Expect energy requirements to change.
A smaller body may require fewer calories to maintain.
Keep resistance training.
Muscle preservation doesn't stop being important when the diet ends.
Don't remain in a calorie deficit forever.
Once the fat-loss phase is complete, transition towards maintenance.
Treat maintenance as part of the intervention.
Learn how much food, activity and structure are required to stabilise the new body weight.
Expect normal fluctuations.
Maintaining 90 kg doesn't mean weighing exactly 90.0 kg every morning.
Establish boundaries for intervention.
Respond to meaningful upward trends early rather than waiting for substantial regain.
Don't abandon the behaviours that worked.
Protein, resistance training, activity, fruit, vegetables, fibre and portion awareness remain relevant.
Allow normal life to happen.
Holidays, restaurants and celebrations aren't failures.
Avoid compensatory restriction.
After periods of higher intake, return to your normal structure rather than punishing yourself.
Continue measuring what matters.
Long-term success is about maintaining improvements in body composition, health and physical function—not simply defending a number on the scales.