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5MinuteConsult Journal Club

Make Your OWN GLP-1


Am J Clin Nutr. 2017 Dec;106(6):1514-1528.  doi: 10.3945/ajcn.117.163246. Epub 2017 Nov 1.

Study Summary/Outcomes

This Systematic Review and Meta analysis evaluated 12 RCT’s (n=609) to determine the influence of soluble fiber on BMI, body weight, body fat, fasting glucose, and fasting insulin. Most of the studies used psyllium fiber in doses around 10 grams per day, divided over 2-17 weeks.

Soluble fiber supplementation reduced:

-- BMI by 0.84 (95% CI: -1.35, -0.32; P = 0.001),

--body weight by 2.52 kg (95% CI: -4.25, -0.79 kg; P = 0.004),

--body fat by 0.41% (95% CI: -0.58%, -0.24%; P < 0.001),

--fasting glucose by 0.17 mmol/L (95% CI: -0.28, -0.06 mmol/L; P = 0.002), and

--fasting insulin by 15.88 pmol/L (95% CI: -29.05, -2.71 pmol/L; P = 0.02) compared with placebo treatments.

While no publication bias was identified, there was moderate levels of heterogeneity found for outcomes.


Consumption of high levels of soluble fiber can decrease risks of obesity.


GLP-1 agents were commercially developed for patients with diabetes through some process involving geckos. After months of completing prior authorizations for GLP-1 agents for my Type 2 Diabetic patients, approvals began to come through. Soon, media outlets began singing their praises, and the supply of these medications dwindled. Everyone, even those without diabetes, wants GLP-1 agonists for their weight control abilities. Their demand now far exceeds their supple.

But you can make your own GLP-1. This occurs in the gut, where soluble fiber fermentation in the colon produces short chain fatty acids (SCFA) like butyrate and carnitine. These SCFA’s stimulate the production of GLP-1, which increases insulin production and decreases glucagon production. They increase production of Peptide YY (PYY) which increases glucose update in muscle and adipose tissue. The SCFA’s also decrease gluconeogenesis.

This study builds on our knowledge that soluble fiber intake has a strong evidence base of being protective against obesity. The challenge is getting adequate soluble fiber in diets. Total fiber intake is recommended at 25-30 grams daily, which correlates with 7-10 servings of fruit and vegetables per day. This is both expensive and requires planning. A possible short cut is adding 10 grams of soluble fiber to patients’ daily routine, reducing their fruit and vegetable intake to 5-7 servings.

Psyllium is the most successful soluble fiber to reduce weight and lower Hbg A1c.  To get 10 grams per day, it can be taken as a powder (1 rounded tsp 3 times a day) or as 500 mg capsules (requiring 6 capsules 3 times a day).

For your patients looking for a GLP-1 prescription, especially for those who have yet to develop T2DM, encourage them to make their own. There is little downside to this, with potential significant benefit.

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