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[209.85.220.41]) by mx.google.com with SMTPS id 71dfb90a1353d-56fa93d8fd7sor9548600e0c.7.2026.04.25.18.07.56 for (Google Transport Security); Sat, 25 Apr 2026 18:07:56 -0700 (PDT) Received-SPF: pass (google.com: domain of tjphuhs@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20251104 header.b=coi1wr37; spf=pass (google.com: domain of tjphuhs@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=tjphuhs@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com; dara=pass header.i=@gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1777165676; x=1777770476; dara=google.com; h=mime-version:subject:references:in-reply-to:message-id:to:from:date :from:to:cc:subject:date:message-id:reply-to; bh=/030RFCamLnlnbZnkXZ05ycWGGTk+bZu4HNb55iaF+M=; b=coi1wr37BDpQoerdDM1Av3OaW8PtnTqREObxivli1F4zjQYmOotBWsbE3a79KXtwa7 nWhJ7kDVR8KbLOr/n+tQij3kKoFH/fsnwp9IVZw+xV9IYJMJ/VX4cPHIZYJePXTIt68K 2VD6vOhMU57QjRVvHMpa5XiUvudMS77uxR/fOt8HH87NhbcYRfp/3Sy+0zaJfIRLXX+9 jkYF5JaZL9JfqEnVVCrGepZVM8gyeuuq1+rvMJvS9+uMhcQdo49Qdd7n17HZEGlhcpwH pSKjdVcwEgPFJXeGsMQvCKSsOnqDhtmw8dNk4Gke1v4uvJ3cTLKZFP+tmzr9L9sg4kQT sZJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777165676; x=1777770476; h=mime-version:subject:references:in-reply-to:message-id:to:from:date :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=/030RFCamLnlnbZnkXZ05ycWGGTk+bZu4HNb55iaF+M=; b=idLzme1G/NCSPM1c7F+XiZLrOG+/dfHDIBSrNU7GbyDHsyi4fSlxJRThyr7/GG14BK Ncl9tEN5d0zLhMY3FrmOmaPf0Sh8R1Ei1vTgWGviDcuCDHUYOyCPPJB42atys3cuUas/ Np2P73RAliRCc6LRM7wi3Q5nQUeoTpnFz+YQQE8ZUOMFus2YPUgIyaGuB1GuEBaCIgPW /mfku4TiYibX/btQW8/Mq+xmX5jc28uztVtYyQpuxM2GPM0V16U7a1Eq28DJhIOAdbUw ZvGwSJlUespAE1NxTAwQucNG3oyDcDxwb36ih1x+ebFHCdLDVcUfIvuF7uhCr5tsOFFA o/qQ== X-Gm-Message-State: AOJu0YwAl1WEQ4Ff1dxr8eCW5xavi+XYwzm3G0dRTl4LY6nRZboJ9T88 iEj/TosoeJAYiiX5PTpVpi8Fz8We1MKsrbo7CWn7KJxMMAQBUxSpE/vbtzUoukl5 X-Gm-Gg: AeBDiesVVGIrrFDRUC/s0PIcfAL8h7Rp737vwZROQGNL0fdynMb8p9sXIYO/+R75RCf yiq/2GOkA2Y2ANtST/YzcHnb4xRFlqrfIcc0qeGG+ZAk55p0REra7hCELkXFcBNWeb4U6C5j5+F YdWadvgor/2j3R7NzzmIljjiiX8G95GrTV9JklBWh7Wj+023WbTd7g8+zvXGxLO4dwNFPqxKD80 GzwRXyUqOiCK/H0FCUFamHp+npNqHz0ArTZe3TXU1EStQF5LjlhmVrDRBiyKlWwrkO9fRe4laDc yGPdgTY7EFVpmAqjHBeYeS2dSUwLLUrZqnjKbDbobBgmt1JlkPeUxPReu/JIPcZEUONMacY4rpm gFpr5MquuZQ4+mPTur0baseZNGQ8GD+rnp104ZeeMidR8CCsqOrNje1d64Qk/A6ZEZQW9fvJFb5 q9yyzGvnA9JEfYjEsXI+ISRfVElQgqo9eSCOm+u5dwViozWg== X-Received: by 2002:a05:6122:8d3:b0:56c:d5cd:1e7c with SMTP id 71dfb90a1353d-56fa58856b1mr19251189e0c.5.1777165675219; Sat, 25 Apr 2026 18:07:55 -0700 (PDT) Return-Path: Received: from [192.168.1.81] ([97.106.1.95]) by smtp.gmail.com with ESMTPSA id 71dfb90a1353d-56fa9332036sm15451007e0c.15.2026.04.25.18.07.53 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 25 Apr 2026 18:07:53 -0700 (PDT) Date: Sat, 25 Apr 2026 21:07:43 -0400 From: tjphuhs@gmail.com To: "=?utf-8?Q?oc.tjphuhs=40gmail.com?=" Message-ID: <3ab9c490-7ece-43c4-a25c-da6a2b1059e0@Spark> In-Reply-To: <20260425195450.3.5a1a6611e884ff7a@mg-d1.substack.com> References: <20260425195450.3.5a1a6611e884ff7a@mg-d1.substack.com> Subject: Fwd: GLP-1s and Slowed Gastric Emptying Part 2: What About Nutrient Absorption? X-Readdle-Message-ID: 3ab9c490-7ece-43c4-a25c-da6a2b1059e0@Spark MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="69ed6568_730c8d86_4674" --69ed6568_730c8d86_4674 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline ---------- =46orwarded message ---------- =46rom: Derek from Research Radar Date: Apr 25, 2026 at 3:55=E2=80=AFPM -0400 To: tjphuhs=40gmail.com Subject: GLP-1s and Slowed Gastric Emptying Part 2: What About Nutrient A= bsorption=3F > After the first post on medication absorption, a lot of you asked the n= atural follow-up question: what about food=3F > =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0= =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2= =AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2= =A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87= =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F= =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80= =87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD= =8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2= =80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD= =CD=8F =C2=A0 =E2=80=87 =C2=AD=CD=8F =C2=A0 =E2=80=87 =C2=AD > =46orwarded this email=3F Subscribe here for more > GLP-1s and Slowed Gastric Emptying Part 2: What About Nutrient Absorpti= on=3F > Derek > Apr 25 > > READ IN APP > > After the first post on medication absorption, a lot of you asked the n= atural follow-up question: what about food=3F What about nutrients=3F If = gastric emptying is slowed dramatically, are we actually absorbing more f= rom our meals because food sits in the stomach longer=3F Or is something = else going on=3F > Upgrade to paid > There=E2=80=99s a popular claim floating around that slowed gastric emp= tying means =E2=80=9Cyou digest your food better=E2=80=9D =E2=80=94 and l= ike most popular claims, it=E2=80=99s partially true, partially misleadin= g, and worth unpacking properly. > Let=E2=80=99s walk through it. > The Mechanism Recap > Quick refresher from Part 1: GLP-1 receptor agonists slow gastric empty= ing by reducing antral contractility, increasing pyloric tone, and dampen= ing the migrating motor complex. =46ood sits in the stomach longer. The r= elease of chyme into the small intestine becomes slower and more gradual.= > The intuitive leap people make is: longer time in the stomach equals mo= re breakdown equals better absorption downstream. Sounds reasonable. Real= ity is more nuanced. > What Actually Happens to Nutrient Absorption > Here=E2=80=99s the key distinction =E2=80=94 gastric emptying and nutri= ent absorption are two different processes happening in two different pla= ces. > The stomach=E2=80=99s main jobs are mechanical breakdown and acid/pepsi= n denaturation of proteins. The actual absorption of macronutrients and m= ost micronutrients happens in the small intestine. So slowing the stomach= doesn=E2=80=99t directly mean =E2=80=9Cmore absorption=E2=80=9D =E2=80=94= it means food is being released into the small intestine on a delayed, s= moothed-out timeline. > What the literature actually shows for GLP-1 users: > Macronutrient absorption is largely preserved. Protein, carbs, fats =E2= =80=94 the small intestine still absorbs them effectively. Total caloric = absorption from a given meal isn=E2=80=99t meaningfully reduced. The curv= e is just stretched out. > Postprandial glucose excursions are blunted. This is one of the most we= ll-documented effects. Because carbs trickle into the small intestine mor= e slowly, blood glucose rises more gradually. This is part of how GLP-1s = improve glycemic control =E2=80=94 not by blocking carb absorption, but b= y smoothing the delivery. > Gastric digestion of protein may be more thorough. This is the kernel o= f truth in the =E2=80=9Cyou digest better=E2=80=9D claim. With food sitti= ng in acidic gastric conditions longer, protein denaturation by pepsin ha= s more time to occur. Whether this translates to meaningfully better down= stream amino acid absorption is less clear in the human data, but mechani= stically it=E2=80=99s plausible. > =46at digestion timing shifts. =46ats normally slow gastric emptying on= their own as a feedback signal. On a GLP-1, that signal is layered on to= p of an already-slowed system. =46at-heavy meals can sit particularly lon= g, which is part of why high-fat meals tend to produce the worst GI side = effects on these protocols. > Specific Nutrient Issues That Have Popped Up > This is where the rubber meets the road. Across the broader GLP-1 user = base =E2=80=94 both clinical and community-reported =E2=80=94 certain nut= rient deficiencies and suboptimal labs have shown up consistently enough = that they=E2=80=99re worth flagging individually. > Protein and lean mass loss. This is the big one. Studies on semaglutide= weight loss have shown that 25=E2=80=9340% of total weight lost can come= from lean mass when protein intake and resistance training aren=E2=80=99= t prioritized. The mechanism isn=E2=80=99t a protein absorption problem =E2= =80=94 it=E2=80=99s that users are eating dramatically less total protein= because appetite is suppressed across the board. Combined with reduced t= raining stimulus from low-energy availability, the body has every reason = to drop muscle. This is the most consistent and most preventable issue on= GLP-1 protocols. > B12 (cobalamin). Showed up early in GLP-1 literature and continues to b= e reported. B12 absorption requires intrinsic factor produced by gastric = parietal cells, and the absorption itself happens in the terminal ileum. = Reduced overall food intake plus altered gastric environment can produce = suboptimal B12 status over months on protocol. Symptoms can be vague =E2=80= =94 fatigue, brain fog, neuropathy in worse cases. Worth checking on bloo= dwork. > Iron. Iron absorption in the duodenum is dependent on gastric acid for = solubilization, particularly for non-heme iron from plant sources. GLP-1s= appear to reduce gastric acid output in some users, and combined with re= duced red meat intake (which is common because protein-heavy meals often = feel the worst), iron status can drift downward. Women with menstrual los= ses are at particular risk here. > Magnesium. Often shows up as cramping, restless legs, sleep disturbance= s, or muscle twitches. Multifactorial =E2=80=94 reduced food intake, incr= eased GI losses (especially during dose escalation when GI side effects a= re worst), and the fact that magnesium is one of the most common borderli= ne-low nutrients in the general population even before adding a GLP-1. > Potassium and sodium. Electrolyte disturbances are common, especially d= uring dose escalation. Reduced food intake means reduced potassium intake= (most people get the majority of their potassium from food, not suppleme= nts), and reduced sodium intake combined with any GI losses can produce r= eal symptoms =E2=80=94 lightheadedness on standing, fatigue, headaches, m= uscle weakness. The =E2=80=9CGLP-1 keto flu=E2=80=9D people describe in t= he first weeks is largely an electrolyte story. > Vitamin D. Not necessarily an absorption issue =E2=80=94 more an intake= issue, since vitamin D-rich foods (fatty fish, fortified dairy, eggs) of= ten drop out of the diet when appetite tanks. Pre-existing low vitamin D = in the population gets worse, not better, on protocol. > Calcium. Calcium absorption depends on gastric acid for solubility and = on adequate vitamin D status. Both can shift on GLP-1 protocols. Long-ter= m concern is bone density, particularly in users on extended protocols wh= o are also losing weight rapidly =E2=80=94 bone mass loss has been docume= nted alongside lean mass loss in some semaglutide and tirzepatide studies= . > Thiamine (B1). Less commonly discussed but worth mentioning. Thiamine h= as limited body stores (only 2=E2=80=933 weeks worth) and requires consis= tent intake. Cases of thiamine deficiency have been reported in patients = on GLP-1s with significant intake reduction or persistent vomiting during= dose escalation. The clinical presentation can include neurological symp= toms and is one of the more serious nutrient issues that=E2=80=99s emerge= d. > Hydration / fluid balance. Not a nutrient per se, but worth grouping he= re. Reduced food intake means reduced incidental water intake (food carri= es more water than people realize). Combined with reduced thirst signalin= g that some users report, dehydration is one of the most common practical= issues =E2=80=94 and it amplifies a lot of the other symptoms above. > The Pattern Behind All of This > Notice the through-line =E2=80=94 most of these issues aren=E2=80=99t a= ctually about altered absorption from slowed gastric emptying. They=E2=80= =99re about dramatically reduced intake, layered on top of slightly alter= ed absorption conditions, layered on top of pre-existing borderline statu= s in the general population. > The reduced intake piece is doing the heavy lifting. If someone=E2=80=99= s eating 40% less food across the board, they=E2=80=99re getting 40% less= of everything in that food. That=E2=80=99s not an absorption problem =E2= =80=94 that=E2=80=99s an intake problem. But the two get conflated consta= ntly. > So Is It True That You =E2=80=9CDigest Better=E2=80=9D=3F > Partially. The longer gastric residence time does likely improve mechan= ical and chemical breakdown of food, particularly proteins. That=E2=80=99= s the legitimate kernel. > What it doesn=E2=80=99t mean is that you=E2=80=99re extracting more tot= al nutrition from less food. The math on caloric and macro absorption doe= sn=E2=80=99t really change. What changes is the kinetics =E2=80=94 same t= otal nutrition, delivered on a stretched-out curve. > The Practical Takeaway > A few things worth keeping in mind on a GLP-1 protocol: > Protein intake matters more, not less. Because total food intake drops = significantly for most users, and because muscle preservation depends on = hitting adequate protein, the protein piece becomes proportionally more i= mportant. Slower gastric emptying doesn=E2=80=99t fix an underdose =E2=80= =94 it just changes the timing of an adequate one. > Hydration and electrolytes need attention. Reduced food intake means re= duced incidental fluid and electrolyte intake. This is one of the more co= mmon practical issues users run into, and it shows up early. > Micronutrient density matters. When total volume drops, every meal need= s to do more nutritional work. This is where multivitamin or targeted sup= plementation conversations come up, and where bloodwork on longer protoco= ls actually starts to earn its keep =E2=80=94 particularly for B12, iron,= vitamin D, and magnesium. > Resistance training is non-negotiable for lean mass. The lean mass loss= data on GLP-1s is the most consistent finding across studies. Adequate p= rotein plus actual training stimulus is the only thing that meaningfully = shifts that curve. > Don=E2=80=99t interpret slower digestion as =E2=80=9Cbetter digestion=E2= =80=9D in a way that lets you eat less and call it equivalent. It=E2=80=99= s not. The math on total nutrition still has to work out. The GLP-1 chang= es the curve, not the conservation of mass. > The framing from Part 1 applies here too: slower does not mean less, bu= t it also doesn=E2=80=99t mean more. The kinetics shift; the totals mostl= y don=E2=80=99t. Where things actually go wrong on GLP-1 protocols isn=E2= =80=99t usually absorption =E2=80=94 it=E2=80=99s the dramatic reduction = in intake that gets ignored because the appetite suppression is doing its= job. > Pay attention to what you=E2=80=99re putting in. Slowed gastric emptyin= g is doing interesting things to the timing, but it can=E2=80=99t manufac= ture nutrition out of food that isn=E2=80=99t there. > This article is for research and educational purposes only. The compoun= ds and protocols discussed are intended for in vitro and laboratory resea= rch use. Nothing in this article constitutes medical advice, clinical gui= dance, or recommendations for human consumption. > Upgrade to paid > You're currently a free subscriber to Research Radar. =46or the full ex= perience, upgrade your subscription. > Upgrade to paid > > Share > > > Like > Comment > Restack > > =C2=A9 2026 Derek Pruski > 548 Market Street PMB 72296, San =46rancisco, CA 94104 > Unsubscribe --69ed6568_730c8d86_4674 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline
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=46rom: Derek from Research Radar <derekpruski=40substack.com&g= t;
Date: Apr 25, 2026 at 3:55=E2=80=AFPM -0400
To: tjphuhs=40gmail.com
Subject: GLP-1s and Slowed Gastric Emptying Part 2: What About Nut= rient Absorption=3F

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After the first post on medication absorption, a lot of you aske= d the natural follow-up question: what about food=3F
=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23= 160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80= =87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD= =CD=8F &=23160; =E2=80=87 =C2=AD=CD=8F &=23160; =E2=80=87 =C2=AD
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GLP-1s and Slowed Gastric Emptying Part 2: What About Nutrient Absorptio= n=3F

Derek
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After the first post on medication absor= ption, a lot of you asked the natural follow-up question: what about food= =3F What about nutrients=3F If gastric emptying is slowed dramatically, a= re we actually absorbing more from our meals because food sits in the sto= mach longer=3F Or is something else going on=3F

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There=E2=80=99s a popular claim floating around that s= lowed gastric emptying means =E2=80=9Cyou digest your food better=E2=80=9D= =E2=80=94 and like most popular claims, it=E2=80=99s partially true, par= tially misleading, and worth unpacking properly.

Let=E2=80=99s walk through it.

The Mechanism Recap

Quick refresher from Part 1: GLP-1 receptor agonists s= low gastric emptying by reducing antral contractility, increasing pyloric= tone, and dampening the migrating motor complex. =46ood sits in the stom= ach longer. The release of chyme into the small intestine becomes slower = and more gradual.

The intuitive leap people make is: longer time in the = stomach equals more breakdown equals better absorption downstream. Sounds= reasonable. Reality is more nuanced.

What Actually Happens to Nutrien= t Absorption

Here=E2=80=99s the key distinction =E2=80=94 gastric e= mptying and nutrient absorption are two different processes happening in = two different places.

The stomach=E2=80=99s main jobs are mechanical breakdo= wn and acid/pepsin denaturation of proteins. The actual absorption of mac= ronutrients and most micronutrients happens in the small intestine. So sl= owing the stomach doesn=E2=80=99t directly mean =E2=80=9Cmore absorption=E2= =80=9D =E2=80=94 it means food is being released into the small intestine= on a delayed, smoothed-out timeline.

What the literature actually shows for GLP-1 users:

Macronutrient absorption is largely preserved.= Protein, carbs, fats =E2=80=94 the small intestine still = absorbs them effectively. Total caloric absorption from a given meal isn=E2= =80=99t meaningfully reduced. The curve is just stretched out.

=

Postprandial glucose excursions are blunted. This is one of the most well-documented effects. Because ca= rbs trickle into the small intestine more slowly, blood glucose rises mor= e gradually. This is part of how GLP-1s improve glycemic control =E2=80=94= not by blocking carb absorption, but by smoothing the delivery.

Gastric digestion of protein may be more thoro= ugh. This is the kernel of truth in the =E2=80=9Cyou diges= t better=E2=80=9D claim. With food sitting in acidic gastric conditions l= onger, protein denaturation by pepsin has more time to occur. Whether thi= s translates to meaningfully better downstream amino acid absorption is l= ess clear in the human data, but mechanistically it=E2=80=99s plausible.<= /span>

=46at digestion timing shifts. = =46ats normally slow gastric emptying on their own as a feedback signal. = On a GLP-1, that signal is layered on top of an already-slowed system. =46= at-heavy meals can sit particularly long, which is part of why high-fat m= eals tend to produce the worst GI side effects on these protocols.=

Specific Nutrient Issues That Ha= ve Popped Up

This is where the rubber meets the road. Across the br= oader GLP-1 user base =E2=80=94 both clinical and community-reported =E2=80= =94 certain nutrient deficiencies and suboptimal labs have shown up consi= stently enough that they=E2=80=99re worth flagging individually.

Protein and lean mass loss. Thi= s is the big one. Studies on semaglutide weight loss have shown that 25=E2= =80=9340% of total weight lost can come from lean mass when protein intak= e and resistance training aren=E2=80=99t prioritized. The mechanism isn=E2= =80=99t a protein absorption problem =E2=80=94 it=E2=80=99s that users ar= e eating dramatically less total protein because appetite is suppressed a= cross the board. Combined with reduced training stimulus from low-energy = availability, the body has every reason to drop muscle. This is the most = consistent and most preventable issue on GLP-1 protocols.

B12 (cobalamin). Showed up earl= y in GLP-1 literature and continues to be reported. B12 absorption requir= es intrinsic factor produced by gastric parietal cells, and the absorptio= n itself happens in the terminal ileum. Reduced overall food intake plus = altered gastric environment can produce suboptimal B12 status over months= on protocol. Symptoms can be vague =E2=80=94 fatigue, brain fog, neuropa= thy in worse cases. Worth checking on bloodwork.

Iron. Iron absorption in the du= odenum is dependent on gastric acid for solubilization, particularly for = non-heme iron from plant sources. GLP-1s appear to reduce gastric acid ou= tput in some users, and combined with reduced red meat intake (which is c= ommon because protein-heavy meals often feel the worst), iron status can = drift downward. Women with menstrual losses are at particular risk here.<= /span>

Magnesium. Often shows up as cr= amping, restless legs, sleep disturbances, or muscle twitches. Multifacto= rial =E2=80=94 reduced food intake, increased GI losses (especially durin= g dose escalation when GI side effects are worst), and the fact that magn= esium is one of the most common borderline-low nutrients in the general p= opulation even before adding a GLP-1.

Potassium and sodium. Electroly= te disturbances are common, especially during dose escalation. Reduced fo= od intake means reduced potassium intake (most people get the majority of= their potassium from food, not supplements), and reduced sodium intake c= ombined with any GI losses can produce real symptoms =E2=80=94 lightheade= dness on standing, fatigue, headaches, muscle weakness. The =E2=80=9CGLP-= 1 keto flu=E2=80=9D people describe in the first weeks is largely an elec= trolyte story.

Vitamin D. Not necessarily an a= bsorption issue =E2=80=94 more an intake issue, since vitamin D-rich food= s (fatty fish, fortified dairy, eggs) often drop out of the diet when app= etite tanks. Pre-existing low vitamin D in the population gets worse, not= better, on protocol.

Calcium. Calcium absorption dep= ends on gastric acid for solubility and on adequate vitamin D status. Bot= h can shift on GLP-1 protocols. Long-term concern is bone density, partic= ularly in users on extended protocols who are also losing weight rapidly = =E2=80=94 bone mass loss has been documented alongside lean mass loss in = some semaglutide and tirzepatide studies.

Thiamine (B1). Less commonly di= scussed but worth mentioning. Thiamine has limited body stores (only 2=E2= =80=933 weeks worth) and requires consistent intake. Cases of thiamine de= ficiency have been reported in patients on GLP-1s with significant intake= reduction or persistent vomiting during dose escalation. The clinical pr= esentation can include neurological symptoms and is one of the more serio= us nutrient issues that=E2=80=99s emerged.

Hydration / fluid balance. Not = a nutrient per se, but worth grouping here. Reduced food intake means red= uced incidental water intake (food carries more water than people realize= ). Combined with reduced thirst signaling that some users report, dehydra= tion is one of the most common practical issues =E2=80=94 and it amplifie= s a lot of the other symptoms above.

The Pattern Behind All of This

Notice the through-line =E2=80=94 most of these issues= aren=E2=80=99t actually about altered absorption from slowed gastric emp= tying. They=E2=80=99re about dramatically reduced intake, layered on top = of slightly altered absorption conditions, layered on top of pre-existing= borderline status in the general population.

The reduced intake piece is doing the heavy lifting. I= f someone=E2=80=99s eating 40% less food across the board, they=E2=80=99r= e getting 40% less of everything in that food. That=E2=80=99s not an abso= rption problem =E2=80=94 that=E2=80=99s an intake problem. But the two ge= t conflated constantly.

So Is It True That You =E2=80=9C= Digest Better=E2=80=9D=3F

Partially. The longer gastric residence time does like= ly improve mechanical and chemical breakdown of food, particularly protei= ns. That=E2=80=99s the legitimate kernel.

What it doesn=E2=80=99t mean is that you=E2=80=99= re extracting more total nutrition from less food. The math on caloric an= d macro absorption doesn=E2=80=99t really change. What changes is the kinetics =E2=80=94 same total nutrition, delivered on = a stretched-out curve.

The Practical Takeaway

A few things worth keeping in mind on a GLP-1 protocol= :

Protein intake matters more, not less. Because total food intake drops significantly for most users, and= because muscle preservation depends on hitting adequate protein, the pro= tein piece becomes proportionally more important. Slower gastric emptying= doesn=E2=80=99t fix an underdose =E2=80=94 it just changes the timing of= an adequate one.

Hydration and electrolytes need attention. Reduced food intake means reduced incidental fluid and electr= olyte intake. This is one of the more common practical issues users run i= nto, and it shows up early.

Micronutrient density matters. = When total volume drops, every meal needs to do more nutritional work. Th= is is where multivitamin or targeted supplementation conversations come u= p, and where bloodwork on longer protocols actually starts to earn its ke= ep =E2=80=94 particularly for B12, iron, vitamin D, and magnesium.=

Resistance training is non-negotiable for lean= mass. The lean mass loss data on GLP-1s is the most consi= stent finding across studies. Adequate protein plus actual training stimu= lus is the only thing that meaningfully shifts that curve.

Don=E2=80=99t interpret slower digestion as =E2= =80=9Cbetter digestion=E2=80=9D in a way that lets you eat less and call = it equivalent. It=E2=80=99s not. The math on total nutriti= on still has to work out. The GLP-1 changes the curve, not the conservati= on of mass.

The framing from Part 1 applies here too: slower does = not mean less, but it also doesn=E2=80=99t mean more. The kinetics shift;= the totals mostly don=E2=80=99t. Where things actually go wrong on GLP-1= protocols isn=E2=80=99t usually absorption =E2=80=94 it=E2=80=99s the dr= amatic reduction in intake that gets ignored because the appetite suppres= sion is doing its job.

Pay attention to what you=E2=80=99re putting in. Slowe= d gastric emptying is doing interesting things to the timing, but it can=E2= =80=99t manufacture nutrition out of food that isn=E2=80=99t there.

This article is for research and educational purpo= ses only. The compounds and protocols discussed are intended for in vitro= and laboratory research use. Nothing in this article constitutes medical= advice, clinical guidance, or recommendations for human consumption.

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=C2=A9 2026 Derek Pruski
548 Market Street PMB 72296, San =46rancisco, CA 94104
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