This is a pilot study to explore the effect of 'medical nutritional therapy' in patients diagnosed with post-bariatric hypoglycemia (PBH), 2-4 years after gastric bypass surgery. The study is largely inspired by the findings presented in the meta-analyses from Joslin Diabetes Center, where a treatment strategy is proposed to reduce the symptoms of PBH. This treatment strategy is mainly based on clinical observations and experience, while there is little or no objective data to support that this strategy improves PBH. The data from this pilot study can then be used to set up larger studies where a conclusion on treatment of PBH may be drawn.

Inclusion Criteria:

• patient in Nord-Trøndelag 2-4 years after Roux-en-y gastric bypass surgery
• visits Namsos outpatient clinic for follow-up.
• having at least 3 symptoms of hypoglycemia presented in the dumping severity scale (DSS).
• at least one of these symptoms must be a neuroglycopenic symptom
• all these symptoms have an intensity of 2 or 3 on DSS.

Exclusion Criteria:

• severe surgery-related complication
• revisional surgery
• life threatening health conditions.
• diabetes mellitus or other metabolic diseases
• pregnancy or breast feeding