Biphasic Diet – Successfully Weaning Off an Elemental Diet

By Georgia Marrion

Small intestinal bacterial overgrowth (SIBO) is a complex condition where excess concentrations of particular commensal bacteria atypically migrate to the proximal small intestine, causing gastrointestinal symptoms including pain, bloating, flatulence, bowel irregularities and nutrient malabsorption issues.1-3

The therapeutic management and treatment of SIBO is complex, requiring a specific yet multifaceted approach that is clinically customised to the individual patient. A vital part of an effective SIBO treatment plan is appropriate dietary modification.3,4

One commonly utilised dietary strategy is the elemental diet, where for 2-3 weeks, patients only ingest easily absorbed, pre-digested macronutrients from food supplements.5 This approach has shown significant benefits for the normalisation of breath test results as well as significant symptom improvement.6 However given its short-term duration as well the symptomatic and aetiological complexity of SIBO, appropriate weaning off the elemental diet is an important part of a SIBO treatment plan.

The Biphasic Diet is an effective dietary protocol specifically designed to promote elimination of small intestinal bacterial overgrowth while minimising adverse physical symptoms commonly experienced as a consequence of the release of endotoxins secreted by bacteria and fungi during the ‘die-off’ process. Developed by Dr Nirala Jacobi from the work of Dr Allison Siebecker, the Biphasic Diet is based on a combination of FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) and SCD (Specific Carbohydrate Diet) diets. These diets have been shown to improve symptoms commonly experienced by SIBO patients.7,8

As summarised in Table 1, the Biphasic Diet involves 2 phases, with each phase comprising of 2 parts. The aim of Phase 1 is to remove the primary fuel sources required for pathogenic bacterial growth (dietary fibres and carbohydrates) to reduce their concentrations and promote intestinal mucosal repair, while Phase 2 involves the gradual reintroduction of these foods and restoration of normal small intestinal motility.8,9

The key benefit of the Biphasic Diet is that it provides a therapeutic nutritional basis to support the repair and healing of the mucosal lining when used alongside an evidence-based supplement protocol for the effective therapeutic treatment of SIBO. Another key benefit is that the Biphasic Diet can be customised to each individual SIBO patients’ clinical presentation and needs.

Table 1: Overview of Biphasic Diet10

DURATION 4-6 weeks 4-6 weeks
THERAPEUTIC AIM REDUCE: reducing fermentable starches and fibres to starve bacteria of fuel to initiate die-off. REMOVE: remove residual excess bacteria and fungi.
REPAIR: repair damage to intestinal lining to promote normal digestion/digestive processes. RESTORE: restore normal small intestinal motility.
THERAPEUTIC APPROACH  (DIETARY) Restricted Diet until symptom improvement occurs.

Semi-Restricted Diet following from Restricted Diet Phase.

Semi-Restricted Diet as basis with allowable foods added as appropriate for individual patient.
THERAPEUTIC APPROACH  (SUPPLEMENTAL SUPPORT) Where appropriate, use of supplements to help promote repair intestinal lining and support digestive function. REMOVE: Use of antimicrobial supplements.

RESTORE: Use of prokinetic supplements.


Download the recipe booklet here.

*References available on request