The culprit here is usually consumption of too much carbohydrate or protein, which will translate into increased blood and decreased ketones, it is important to identify all food, beverages, supplements, medications, and oral care products that maybe inferring with ketosis. Ensure protein is consumed in moderation. Often cutting back 5 or 10 g/day will boost ketone levels, but consuming too little protein (<1.2 g/kg reference weight) is not advised.
Check the ingredients of packaged foods, low-carb snack bars, and supplements. Identify which ingredients might be causing an increase in blood sugar and decrease in ketones. Some sugar alcohols like maltitol increase blood sugar. Fibers listed as fructooligosaccharides and oligosaccharides are indigestible, but they can raised blood sugar in some individuals.
Be wary of foods promoted as “sugar-free” and marketed to people with diabetes, as these may be keto-friendly.
There are carbohydrates in some medicine and supplements. A pharmacist may be able to help. The Charlie foundation has a list of low-carb and carb-free supplements and personal hygiene products (https://www.charliefoundation.org/resources-tools/resources-2/low-crab).
Non-steroidal anti- inflammatory drugs can decrease ketones.
Insulin and steroid medications (e.g. prednisone, dexamethasone, or hydrocortisone) are anti-ketogenic. It may be difficult to maintain ketosis while on insulin and/or steroids. Prednisone and dexamethasone are commonly prescribed to control inflammation, and hydrocortisone can be prescribed as a replacement hormone if cortisol levels are low. All steroid medications cause glucose levels to rise but may be included as part of a treatment protocol. Any change in dosage should be supervised by a medical doctor and individuals should not discontinue use without consulting the medical team.
If only urine testing has been performed, have the individual test blood ketone levels to check whether keto-resistance really is occurring. Incorporating moderate exercise is known to promote fatty acid oxidation and moderately increase ketones. Use of MTC oil to tolerance may moderately elevate ketones.