Weight Loss Isn't Just About the Scale: Understanding the Crucial Difference Between Weight Loss and Fat Loss

Losing weight doesn't necessarily mean losing fat

One of the biggest misconceptions in weight loss is believing that shedding pounds equates to shedding fat.
Let me share an experiment: to test how much weight an adult can lose in a single day, an athlete abroad conducted a trial.

Through dietary restriction, diuretic use, sauna sessions, and intense exercise in sweat-inducing garments, he reduced his weight from 94.7kg to 83.4kg in a single day—a loss of nearly 12kg that visibly shrunk his frame. Post-experiment, driven by extreme hunger, he binged on food and reclaimed the lost weight within days, with his body fat remaining virtually unchanged.

Through this experiment, he sought to demonstrate that weight loss is not synonymous with weight reduction. Changes in body weight result from the combined influence of numerous factors. Such extreme, rapid weight-loss methods inevitably lead to more severe rebound effects later on.

Why does weight loss not equate to fat loss?
First, let's examine what constitutes body weight. Water makes up the bulk of the human body, accounting for approximately 60%. Protein and fat each comprise around 20%, with the remainder consisting of trace minerals, carbohydrates, and vitamins. Thus, fat—which constitutes only about 20% of body weight—is not the primary component; water is. True weight loss occurs only when fat is shed. Henceforth, cease labouring under the mistaken belief that reduced weight equates to weight loss. What you shed is predominantly your body's precious water content—especially in rapid weight loss scenarios, where nearly all loss is hydration.

You truly underestimate how stubborn fat is
I suspect many have experienced this during weight loss: yesterday you weighed 101 jin, today the scales show 99 jin—delighted to see your weight dip into double digits.

In this scenario, you've indeed shed 2 jin of weight, but how much actual fat have you lost?
One jin of fat equates to 3,900 kilocalories of energy. This means to lose 2 jin of fat, you'd need to burn a net 7,800 kilocalories!

What does burning 7,800 kcal through exercise actually entail? Let's break it down: an average woman burns 300 kcal per hour jogging. To burn 7,800 kcal, you'd need to jog for 26 hours straight – covering 180 kilometres, or 450 laps around a 400-metre track.

That sounds daunting, so you might think, ‘I'll just stop eating—dieting must work, surely?’ Well, I've calculated that too. To achieve that energy deficit, an average woman would need to abstain from food entirely for a full week!

Why is fat so stubborn? Because the fat on your body is accumulated from long-term energy surpluses. Yet we often feel we ‘starve off’ 2 jin rather quickly—why is that?

That's because what you're shed isn't primarily fat, but water.
You might wonder: if I haven't exercised much or sweated, how did I lose so much water?

When you start dieting, especially cutting out staples, your body loses glycogen fastest. As glycogen departs, it drags significant water with it. For every gram of glycogen lost, 3–4 grams of water are shed.
Thus, both intense exercise and dieting deplete glycogen and water, leading to weight loss.

Losing weight doesn't necessarily mean losing mass
Firstly, if you've incorporated resistance training during your weight loss journey, even if fat decreases, muscle gain may occur. This can leave your weight largely unchanged or even slightly increased. Since muscle is denser than fat, your body becomes firmer, though such changes are difficult to detect in the short term.

Secondly, based on a daily 500-kilocalorie deficit, fat loss peaks at around 50 grams per day. Such a 0.05-kilogram fluctuation is scarcely detectable on scales.

Moreover, scales themselves can be deceptive. Weighing at different times yields varying readings, and different scales may also produce discrepancies.

So how should weight loss be monitored? Fret not—we shall detail effective tracking methods in subsequent chapters.

The greatest danger of focusing solely on weight lies in misleading those who, after following a weight loss plan for some time without seeing changes on the scales, mistakenly conclude their method is ineffective. This leads them to abandon proven approaches in favour of the myriad extreme methods flooding the market, ultimately trapping them in a vicious cycle where they lose weight only to gain it back.

Remember: true weight loss comes from shedding fat. Fat has a high energy density, requiring patience. Rapid weight loss methods shed almost exclusively water weight.