Losing Weight Is Not About Willpower
The short answer
Eating less does make the weight come off — so why does it always stall and come back? What actually decides the outcome is not whether the weight comes off, but whether the body can bear the process while it does. What comes off in the first week is usually water, a body pushed too fast gives up muscle first, and gallstones showed up more often in the group that lost weight faster. If your weight has dropped on its own, without any effort, testing comes first.
Contents
Eat less and the weight comes off. It really does come off.
The more methods someone has already tried, the better they already know what comes next: some weight comes off, it stalls at some point, and after a while it returns. The losing itself happened every time.
So what actually decides the outcome lies elsewhere. Not whether it comes off, but whether the body can bear the process while it does.
I have long put it this way to patients: you lose the weight, and I watch what happens to the body while you do. Below, I will lay out what happens in the body during that process.
What Comes Off First Is Usually Water
Cut carbohydrates and the change in weight in the first week can look large.
The body stores carbohydrate in the form of glycogen, and glycogen holds on to water along with it. When glycogen decreases, the water it was holding leaves with it.
When food intake drops, insulin drops too. When insulin drops, the kidneys hold on to less sodium. When sodium leaves, water follows it out.
So the first week shows a good drop, and then it stalls. The scale was honest, but most of that number was not fat.
Around this time, dizziness, headache, calf cramps, and low energy are common. In a review of people who started a ketogenic diet, those symptoms too clustered in the first few days.
That review also notes, however, that there is not yet a study that measured what actually happened to the body's water and electrolytes at the time these symptoms occurred. Water and sodium loss is the most plausible explanation, not a confirmed cause.
Move Too Fast, and the Body Gives Up Muscle First
The body pulls protein out of muscle to make blood sugar from it, and redirects the energy muscle would have used toward the nervous system instead. Go hungry or stay inactive, and muscle shrinks quickly.
Athletes who were already strength training were split into two groups: one lost 0.7% of body weight per week, the other 1.4%. Both groups did the same training.
Only the slower group gained 2.1% in lean mass. The faster group stayed flat.
Read the numbers precisely and this is what they say: lean mass did not decrease even in the faster group. It simply did not increase. And since both groups were athletes who were training, this cannot be carried over directly to going hungry without exercise. What remains is one thing. Even with the same training, speed alone was enough to split the outcome.
Gallstones Showed Up More Often in the Group That Lost More
The group that ate less lost more weight — 11.1 kilograms versus 8.1 kilograms, a 2.8-kilogram difference once the conditions were matched and calculated.
But people hospitalized for gallstones or who had their gallbladder removed were more than three times as common in the group that ate less. This held even after accounting for the fact that they had lost more weight.
Bile needs to keep flowing. Eating a meal makes the gallbladder squeeze it out, and that is how bile circulates. Go hungry for a long stretch and there is nothing to trigger that squeeze, so cholesterol settles out of the bile that sits stagnant.
What this study speaks to is gallstones alone. It is not saying that losing weight fast triples every kind of problem. Nor is it common — in the faster group, roughly one extra case appeared for every 92 people.
But on this one point, the direction is clear. The group that lost more had more gallstones.
Which Is Why the Word "Margin" Is Needed
Losing weight and the body bearing that loss are two different things.
A body with margin refills its water quickly even after some is lost, and its digestion often returns to normal once a period of hunger has passed. A body with little margin pays the cost elsewhere, even after losing the same amount.
Where it is paid differs from person to person. In the discussion of a time coming when things are not like before, I noted that a shrunken margin touches the softest spot first. Losing weight shrinks that margin all at once, so even the same method over the same period shows up in a different place for each person.
So What I Watch For
Which method to use is the patient's choice. But a severely restrictive approach is something to decide only after first checking the state of the body.
What I watch for during that process is whether dehydration is setting in, and whether the nervous system is becoming excessively excitable — how much water has been lost, and how sleep and digestion have changed.
Losing weight and the body holding up through it do not go separately. Watch only one side, and the cost shows up on the other.
If the Weight Dropped Without Any Effort
If your weight has dropped on its own, this discussion does not come first for you. There is something else that needs to be checked first.
Willpower gets you as far as losing the weight.
Push through on willpower alone, and the weight does come off — but the cost is paid elsewhere. It is paid in water, in muscle, in bile.
And that cost changes depending on the speed and method of losing it. I told the other half of this story in why not losing weight is not a matter of willpower.
Written by Dr. Heo Ji-young (PhD in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)
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