Help! Thanks!?

You do not need the "units of" because it's understood what measurement system you mean... so...

Please enter your height (in centimeters) and weight (in kilograms). This has a bearing on your dietary guidelines.

Putting the measurement system in parenthesis is common when there is a doubt as to which system may be used. Without seeing the entire paragraph, a period may be more appropriate than a semi-colon.

Only if there is some reason to require a scientific accurate measurement (which I doubt) would you add an adjective to modify the height and weight... in which case the sentence would be:

Please enter your exact height (in centimeters) and your exact weight (in kilograms). This has a bearing on your dietary guidelines.

Pleas enter your height clearly in units of centimeters, and weight in units of kilograms; this has a bearing on your dietary guidelines.

Please enter your height in centimeters and your weight in kilograms. Your correct height and weight will be required in order to assess and suggest your individual dietary guidelines.

Please enter your height in centimeters and your weight in kilograms; these will influence your dietary guidelines.

I'm 186 cm tall (5' 9"), and weigh 58kg.

I think I way be a bit underweight.

^of kilograms^