Weight-loss surgery patients got a nutrition protocol in 2008. GLP‑1 patients got guidance in 2025 — written for doctors, and rarely handed to you.
Here's what's actually happening in your body on a GLP‑1, in order, with the parts that rarely come up at the appointment.
If the first few weeks on a GLP‑1 felt like eating a huge meal too fast — every time, no matter what or how little you ate — you're not imagining it, and you're not the unlucky one. Digestive side effects show up in somewhere between 4 and 7 out of every 10 people on these medications.2 Constipation, when it hits, tends to sit for six to ten weeks before it lets up. And then there's the sulfur burping nobody mentions at the pharmacy counter until you're the one doing it in a meeting.
None of that means something's wrong with you. It means something predictable is happening, on a predictable timeline, to a predictable share of people — and there's a reason it hasn't been explained to you yet. Here's the mechanism, in order.
It's not bad luck. It's not weakness. It's a documented mechanism.
GLP‑1 medications work in part by slowing how fast your stomach empties. That's the mechanism doing its job, and it's measurable: among 35,183 people having an endoscopy, those on a GLP‑1 were about four times as likely to still have food in their stomach (13.6% vs. 2.3%).3 Food that sits longer is where the fullness, the nausea and the sulfur burps come from. Things moving more slowly further down is where the constipation comes from.
in real-world studies
in the stomach at endoscopy
Belching gets reported by about 9 in every 100 people in trials5 — few enough that it can feel like you're the only one, and common enough that you're not. You are not an outlier. This is the base rate.
The real math: you're eating up to a third less. Your body's requirements didn't move an inch.
Before the numbers, think about what you actually ate yesterday. Not what you meant to eat — what landed on a plate and got finished.
That's the part that doesn't get talked about: the drug turned your appetite down. It didn't turn down what your body needs to run. GLP‑1 medications cut energy intake by 16–39% compared with placebo.6 In one study of 387 people on these medications, average protein intake was 33.4g a day, and fewer than 1 in 10 met the recommendation.7 Eat up to a third less, and up to a third of the nutrients that used to ride along with that food stop showing up too. Nothing is broken. The arithmetic just stopped working.
deficiency by month 12
Why nobody's told you — and it's not because your doctor dropped the ball.
Since 2008, weight-loss surgery patients have walked out of the clinic with a nutrition protocol: lifelong daily supplements for every patient, specific doses like at least 12mg of thiamin a day, B12 for everyone, and scheduled monitoring. The guidelines were updated in 2016 with 92 recommendations, 79 of them new.10
Then a medication arrived that cuts how much people eat, without the surgery. Millions of prescriptions. The first joint nutrition advisory for it came out in 2025, from four medical societies — written for clinicians, and by its own account, nutrition support alongside these drugs still isn't widespread.6 A randomized trial on whether a multivitamin helps people on GLP‑1s is still underway.11
It's not your prescriber's fault, either. 83% of physicians — roughly 5 in 6 — cite time as a barrier to nutrition counseling, and 62% say they lack the nutrition training for it.12 The guidance that exists was written for them, not handed to you.
The free fix everyone recommends might be working against you.
The most common advice for the sulfur burps — cut cruciferous vegetables, alliums, eggs and red meat — does stop the burps for a lot of people. It also cuts some of the easiest everyday sources of folate, B12, iron and zinc, plus the prebiotic fiber in garlic and onions, at exactly the moment you're already eating less. The most common fix for the most embarrassing symptom quietly deepens the gap underneath it.
The other place this shows up: the drugstore multivitamin. Most use ferrous sulfate for iron, because it's the cheapest form. Across 43 trials, ferrous sulfate significantly raised the odds of stomach side effects compared with placebo.13 And in two randomized trials, black stools were reported by 31% of women taking ferrous sulfate — versus 8% on ferrous bisglycinate, the form in ours.14 Your $12 bottle was built for a normal gut with normal intake. On a slowed gut, some of it works against you.
This isn't a knock on your instincts — you assembled a plan out of nothing, from strangers on the internet, because nobody handed you one. Good instincts, wrong tools.
Side effects, not cost, are the top reason people stop.
In one real-world analysis of 1,374 patients, 26.8% stopped their GLP‑1 because of adverse reactions, versus 14.4% over cost.1 Nausea is the number one stated reason, and month three is where most people who quit, quit. Up to 85% of patients — roughly 6 in every 7 — are off these medications within two years.15
And stopping doesn't just pause progress. A meta-analysis of eight randomized trials found people regain an average of 9.69 kg — about 21 pounds — in the year after they stop.16 In the semaglutide trial that followed people after stopping, about two thirds of the weight lost had come back within a year.17
To be clear about what we're not saying: this isn't a treatment for side effects, and nothing proves a supplement keeps anyone on their medication. What it's built for is day-to-day digestive comfort and nutrition during the months that tend to be hardest.
What a protocol built for this actually looks like.
This is where the Understory Daily Micronutrient & Digestive Protocol comes in — and it's worth saying plainly what it is and isn't. It's not a replacement for your medication, it's not a way to "boost" it, and it doesn't touch the mechanism your drug runs on. It's two capsules with dinner: a digestive-comfort half for a gut that's working slower than it used to, and a nutrient half in forms chosen for how well they're tolerated.
Also in each serving: B6 as P5P (26mg), vitamin D3 (50mcg), magnesium (200mg), biotin (5mcg), BioPerine® black pepper extract (5mg) to support absorption, and ashwagandha in the Energy & Vitality Complex (126mg). Every batch is third-party tested, with a Certificate of Analysis.
Where to start.
If you've read this far, you already know more about what's happening in your body than most people get told at the pharmacy counter. What comes next isn't complicated.
- $48.00/month on subscribe & save — about $1.60 a day — or $60.00 one-time. A 3-month supply is also available for $150.00, with free shipping. You're not locked in.
- 60-day money-back guarantee — long enough to judge it across a full dose-increase cycle, not a week that catches you mid-change.
- Cancel any time from your account, no phone call.
- Third-party tested, with a Certificate of Analysis for every batch.
Prefer to check with your prescriber first?
That's the right instinct. Get a one-page printable of questions to bring to your next appointment — what to ask about nutrients, which labs are worth requesting, and how to bring up the symptoms most people don't mention.