Dr.EndoEP said:Fiber trials in this population are thin, and most of what gets quoted is extrapolated from idiopathic constipation in people eating normally.
This answered a question I did not know how to ask.
From the other side of the consultation, briefly.
Gastroparesis symptoms with constipation: the delayed gastric emptying from GLP-1 agonists can cause early satiety, bloating, and feeling "full" for hours after a small meal.
Tips: eat your protein FIRST (most important macro), then vegetables, then carbs last. Chew thoroughly — 20-30 chews per bite isn't excessive. Avoid carbonated beverages with meals. If symptoms are severe, your doctor may recommend a gastric emptying study.
EndoResFellow said:Acid reflux and constipation: I developed GERD symptoms around week 3 that I'd never had before.
Gastric emptying studies and constipation: semaglutide delays gastric emptying by ~40% at steady state, as measured by acetaminophen absorption testing and scintigraphy[1].
Clinically relevant implications:
Importantly, the gastric emptying delay attenuates with continued use (tachyphylaxis), which correlates with the transient nature of GI side effects.
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Shop Reference StandardsDr.EndoIndy said:The mechanism is slowed transit plus reduced intake, and that combination determines which interventions work.
Drug interaction alert relevant to constipation: if you take oral levothyroxine (Synthroid), GLP-1 agonists can reduce absorption due to delayed gastric emptying. My TSH drifted up after starting semaglutide.
Solution: take levothyroxine on an empty stomach, 60 minutes before any food, and have your TSH rechecked 6-8 weeks after starting or changing GLP-1 dose. My endo had to increase my Synthroid by 12.5mcg.