@Chuck, what is the cause of the gastroparesis? Is her vagus nerve intact?
The most common causes I’m aware of are diabetes and also weight loss surgery. Some medications, opiates are notorious for this because they depress the CNS, also cause it. I ask because if it’s diabetes it should possibly improve as the diet is resolved. Usually 50g of fat is the maintenance part of the diet.
So the reason for the fat limitation is that it delays gastric emptying - this is actually part of why keto is high satiety. A common complication of GP is that people get dehydrated or cannot digest food properly. Having said that, I would proceed cautiously if she still has it. You can easily do a modified ketogenic diet that is a little lower in fat and slowly increase the fat weekly to see if side effects return. Caution is key. Dense meats (like pork and red meat) also drastically slow gastric emptying. Has she been able to eat these and tolerate them?
Eventually, it might be best to consult a doctor if it’s been more than 5 years to see what’s up, depending on the cause, too, since it can be progressive (or go away).
Some handy tips:
- Eat many small meals a day (this helps the stomach empty faster).
- Cutting out veggies might actually cause dramatic improvement. I’d avoid fiber altogether, as fiber exacerbates it more than fat.
- Many people also see improvement avoiding all dairy and grain products (these can ferment and also slow emptying, among other issues).
Honestly, based on experience with it, she might do fine eating a super high fat diet, though. It typically moves things through the system faster. However, IANAD and she needs to talk to one. It really depends on the cause of the gastroparesis to a great degree.