Regarding probiotics specifically , expert guidance suggests: No major medical organization currently recommends probiotics as a weight loss intervention Patients interested in gut health optimization should focus on dietary fiber (25g daily for women, 38g daily for men) and fermented foods rather than supplements [29] If patients choose to use probiotics, they should inform their healthcare provider and select products from reputable manufacturers with third-party testing (USP, NSF, ConsumerLab) Clinical referral triggers include patients seeking probiotics as alternatives to indicated medical therapy, those with unrealistic weight loss expectations, or individuals with eating disorders
It then asks why well-powered trials have largely failed where smaller studies and real-world data succeeded, with attention to brain exposure, trial design, and patient selection, and outlines what the next generation of studies will need to test the hypothesis properly

CP Lab Chemicals Propionyl-L-carnitine Hydrochloride (C10H20ClNO4), 25 grams Part Number: CP-89967749-25g Lead Time: 5-10 days Shipping: FREE SHIPPING on most orders over $50* Quantity: each Size: 25 grams Style: chemical CAS Number: 119793-66-7 Frequently bought together: Description Propionyl-L-carnitine hydrochloride (C10H20ClNO4), 25 grams Material Safety Data Sheet View AllClose Volume: 25g CAS: 119793-66-7 Formula: C10H20ClNO4 Molecular Weight: 253.72 Product Type: Analytical Reagents, Biochemicals, Building Blocks, Organics Harmonized Tariff Code: 29239000 Storage: Ambient Material Safety Data Sheet Terms & Conditions These chemicals are for professional manufacturing, research laboratories and industrial / commercial usage only
It means prioritizing foods that reduce inflammation and avoiding foods that promote it
(PubMed) Bassett JK, Baglietto L, Hodge AM, et al