How much of that 40 kg is muscle, and how to keep it

The number the scale hides

Weight is a poor measure of progress because it never says what was lost. During very rapid loss, a quarter of the total can come from lean tissue rather than fat. Losing forty kilograms of which ten are muscle leaves a person lighter, weaker and with a lower resting metabolic rate than their new size would predict, which is one of the quiet routes into regain two years later. Bioimpedance at each visit answers the question the scale cannot.

Protein first, in doses the stomach accepts

Sixty to eighty grams a day is the floor, and taller or more muscular patients need more. The practical obstacle is volume: a stomach holding 100 to 150 millilitres cannot take thirty grams of protein in one sitting, so the day has to be built around four small deliveries of twenty to twenty-five grams each. Shakes during the first three months are not a marketing product; they are the only realistic way to reach the number.

Resistance work from about week four

Walking starts the day after surgery and matters mostly for clot prevention and bowel function. Muscle needs load. Bands or light weights from roughly week four with the surgeon's clearance, two or three sessions a week, built around squats, rows, presses and carries rather than machines that isolate single muscles. The load has to increase over time or the stimulus disappears. Cardiovascular exercise is good for the heart and does very little to protect lean tissue in a deficit.

What we measure, and when

Body composition is recorded at one, three, six and twelve months alongside weight, and grip strength gives a quick cross-check between visits. If lean mass is falling faster than expected, the response is more protein and more resistance work, not congratulations on a scale reading. Twelve months of dietitian follow-up is included with every bariatric case, and this is the part of it that patients value two years later rather than two weeks later.

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