There are two energy drinks. One gives 10^{-18} calories per litre, the other 1 calorie per litre. You want to find some combination of them which maximizes the total number of calories 10^{-18}x+y, subject to some other constraints, where x,y denote how many litres of each drink you want to intake.
There are two possibilities.
Either you expect x,y to be of reasonable magnitude for a human being to drink, say somewhere about 1 litre. In that case x completely doesn’t matter, including it is way below the numerical resolution of any solver and you should just ignore it in the model.
Or you are expecting that both summands, that is 10^{-18}x and y will be of similar, reasonable order of magnitude, say you expect to drink some single petalitres of the first drink, and some single litres of the other (x\approx 10^{15}, y\approx 1). In this case it is better to express the amount of the first drink, for example, in the number of exalitres X and have an objective of the form X+y and expect a solution of magnitude X\approx 10^{-3}, y\approx 1. This way both the coefficients and the expected solution values become simultaneously more even and therefore manageable.
Expecting anything else is numerically flawed from the start.