For the longest time I have seen trainers, RDs etc. recommend absolute changes in caloric intake. The most popular recommendation by far being to increase/decrease calories by 250 per day. However, 250 calories means different things for different people and I think it’s the wrong approach to take.
Suppose you have someone who weighs 250lbs and is consuming 2500 calories/day in order to lose weight. Reducing intake by 250 calories per day represents a 10% decrease in daily calories. What if the person weighs only 150lbs and is consuming 1500 calories per day in order to lose weight? Reducing calories by 250 per day would equal a 17% decrease in daily calories. This is a pretty sharp drop in intake at once and could have counterproductive results.
A better way to go about it would be to adjust caloric intake by percentage instead of absolute numbers. This way adjustments are relative to the individual and you avoid making adjustments that are too high for some or too low for others. Personally, I always start with a 10% change in calories, regardless of whether someone is looking to lose weight or gain muscle. It’s typically enough to get the person rolling again without any adverse effects that could result from too big a change.