Why You Can't Lose Weight at 150kg (It Isn't Willpower)

You have probably been told that healthy fat loss is 1–2lb (0.5–1kg) a week, that anything faster is dangerous, and that if you are not losing at that rate you must be doing something wrong. That rule is not true for anyone, and it is least true for you.

At 150kg, a well-built plan can produce 1.5–2.5kg (roughly 3–6lb) a week in the early stages. Not through starvation, and not through anything clever. Through arithmetic that works differently at your size than it does at the size the advice was written for.

Here is why, and what it means for what you should actually do this week.

The rule you were given was written for someone else

The 1–2lb a week guideline comes from research and clinical practice aimed at people with a modest amount of fat to lose. Someone at 85kg trying to get to 78kg. For that person it is reasonable advice.

You are not that person, and the difference is not one of degree. Two things change as bodyweight goes up, and they compound.

One: a bigger body burns more

Total daily energy expenditure — everything you burn in a day — scales with how much of you there is. More tissue to keep alive, more mass to move, more work to do the same walk.

A man at 150kg has a substantially higher maintenance than a man at 85kg. That is not a theory, it is why heavier people can eat more without gaining. It also means that a deficit that would be dangerous for a smaller man is unremarkable for you.

Take a 1,000 calorie deficit. For someone whose maintenance is 2,300, that leaves 1,300 to eat — genuinely low, hard to hit protein on, not sustainable for long. For someone whose maintenance is 3,800, the same 1,000 calorie deficit leaves 2,800. That is a normal amount of food. Same deficit. Completely different experience.

This is the point most people miss, so it is worth being precise: a deficit is a number of calories, not a percentage and not a rate. Two men can run an identical 1,000 calorie deficit while one is eating 1,300 and the other 2,800. Only one of them is suffering.

Two: more fat means more tolerance

The second mechanism is about where the energy comes from. Body fat is stored energy. Someone carrying 70kg of it has an enormous reserve available to make up the difference between what they eat and what they burn.

Someone at 12% bodyfat running a large deficit is asking their body to find energy it does not really have spare, and the body responds accordingly — hunger climbs, energy drops, training suffers, and the whole thing falls apart within a fortnight. That experience is real, and it is where the caution in the standard advice comes from.

At 50% bodyfat, that same deficit is drawing on a supply that is, for practical purposes, deep. Diet fatigue arrives much later and much more gently.

These are two separate points and they multiply. Your body can tolerate a bigger deficit, and your maintenance is high enough to make a bigger deficit possible without eating an absurdly small amount. Fatter means both things at once.

What actually limits you

Not the deficit. The floor is what you eat, not what you subtract.

The question is never "how big a deficit can I run" — it is "how low does my intake go before this becomes a bad idea". Those sound like the same question and they are not. At your maintenance you can produce a large deficit while still eating a reasonable amount of food, hitting your protein, and having enough energy to train. That is the whole advantage, and it is why this works for you and would not work for someone lighter.

Three things bound it in practice:

• Protein has to stay high. You are trying to lose fat, not mass. Protein is what makes the difference between the two, and it does not become optional because you are in a hurry.
• You have to be lifting. Resistance training is the signal that tells your body the muscle is worth keeping. Without it, a large deficit takes whatever is easiest to give up.
• Absolute intake stays sensible. Not "as low as you can bear". Sensible. If the arithmetic tells you to eat less than the floor, you increase output or accept a slower rate — you do not eat less.

It is self-limiting, which is the reassuring part

Here is what nobody tells you and what makes this approach less reckless than it sounds: the advantage disappears on its own as you use it.

At 150kg you have a high maintenance and a deep reserve. By 120kg both have shrunk. The deficit that was comfortable at the start is no longer available, and the rate slows whether you like it or not.

You cannot ride this all the way down. You get the fast phase at the beginning, when you most need the evidence that something is working, and then the terms change. That is not a failure of the method. It is the method working exactly as the arithmetic says it should — and it is why the three phases of fat loss matter more than any single number.

What this means for you this week

Stop calibrating your expectations to advice written for a smaller man. If you have been running a 300 calorie deficit and wondering why five months produced almost nothing, the answer is not that you lack discipline. It is that 300 calories against a 3,800 maintenance is under 8%. It is a rounding error. You have been doing something that could not have worked.

Set the deficit from your actual maintenance, not from a magazine number. Your maintenance is a function of your bodyweight, and yours is high. Use it.

Then recalculate as you get lighter. This is the step almost everyone skips, and it is the single most common reason a diet that worked in month one has stopped working by month five. Your maintenance falls as you do. The intake that produced a large deficit at 150kg may be close to maintenance at 120kg. Same food, same effort, no results — and it feels like your body has broken when it is only arithmetic.

Expect the scale to lie to you regularly. Bodyweight moves for reasons that have nothing to do with fat, and aggressive methods make it move more, not less. Weigh daily, track the seven-day average, and judge the average.

What this is not

It is not a licence to eat as little as possible. The rate comes from having a high maintenance to work against, not from heroics at the dinner table.

It is not permanent. It is a window that closes as you get lighter, and the work changes when it does.

It is not comfortable. Nothing here is easy — it is just honest about what is possible, which is more than the 1–2lb rule ever was.

And it is not medical advice. If you have a condition or take medication, speak to your doctor before changing anything. We are not clinicians and we are not going to pretend otherwise.

Where to start

Work out your maintenance from your current bodyweight. Set an intake that produces a real deficit while leaving you enough food to hit your protein and train. Weigh daily, track the average, and recalculate as the number comes down.

That is genuinely most of it. The difficulty was never the plan — it was believing that the plan applies to you, when every source you have read was quietly written for somebody else.

Mark did this from 152kg. He is 62kg down and it stayed off. Rory, who he trains, dropped 13kg in his first six weeks. Neither of them did anything you cannot do.