I don't think you have to fast while using D-Mannose, though you might want to space out meals after taking it. For example in the morning take d-mannose with water then wait at least an hour before your first meal of the day or drinking anything. I think the regimen you posted would be for treating a bladder infection or UTI.
D-Mannose
How much d-mannose do I need to take, and how often?
For an infection, you will need to take ½ - 1 tsp every 2 hours you are awake for the first 2 days. Do not dilute the dose by mixing the powder in a full glass of water. It should mix with 1-3 ounces of liquid, preferably water, to ensure the dose is concentrated and you are getting all of the Manno-max at the same time. DO NOT MIX WITH CITRUS JUICES.
According to Dr. Jonathan V. Wright, editor of Nutrition and Healing, if the infection is not considerably better within 24 hours, it is probably not caused by E.coli, Streptococcus, or Psuedomonas bacteria, please consult your physician.
VERY IMPORTANT – Take ½ - 1 tsp at least 45-60 minutes before relations and ½ - 1 teaspoon immediately after relations whether or not you are on a regular maintenance dose. Manno-Max d-Mannose can also be used for maintenance and prevention.
Will d-mannose react with the prescription drugs I’m taking?
Since d-mannose is a natural food substance, and not a drug, it will not interact with any other prescription drugs an individual is taking. It is completely safe to take d-mannose simultaneously with any prescription drug.
What is the shelf life of D-mannose?
The shelf life of d-mannose is approximately 3 years.
Can bacteria build up a resistance to D-mannose?
No. D-Mannose is not a drug and it does not kill bacteria. D-mannose merely prevents bacteria from attaching to cell walls, enabling the body to eliminate them naturally.
Does D-mannose feed Candida yeast?
D-mannose does not feed Candida yeast because the body does not metabolize it the same way it does with other sugars.