Why the Scale Is a Terrible Measure of Fat Loss Body weight fluctuates by 1โ€“3kg daily based on water retention, glycogen stores, bowel contents, and sodium intake โ€” none of which reflect actual fat loss. Someone who loses 500g of fat in a week but increases water retention by 1.5kg will see the scale go up 1kg despite making excellent progress. This is one of the leading causes of diet abandonment: people stop doing the right things because the scale gives them the wrong signal. Consider Sarah, who started a new training program combining strength training with moderate cardio. After fourโ€ฆ