In fructose 1,6 bisphosphatase (FBPase) deficiency, management aims to prevent hypoglycaemia and lactic acidosis by avoiding prolonged fasting, particularly during febrile illness. Although the need for an emergency regimen to avoid metabolic decompensation is well established at times of illness, there is uncertainty about the need for other dietary management strategies such as sucrose or fructose restriction. We assessed international differences in the dietary management of FBPase deficiency. A cross-sectional questionnaire (13 questions) was emailed to all members of the Society for the Study of Inborn Errors of Metabolism (SSIEM) and a wide database of inherited metabolic disorder dietitians. Thirty-six centres reported the dietary prescriptions of 126 patients with FBPase deficiency. Patients’ age at questionnaire completion was: 1-10y, 46% (n = 58), 11-16y, 21% (n = 27), and >16y, 33% (n = 41). Diagnostic age was: 16y, 2% (n = 2). Seventy-five per cent of centres advocated dietary restrictions. This included restriction of: high sucrose foods only (n = 7 centres, 19%); fruit and sugary foods (n = 4, 11%); fruit, vegetables and sugary foods (n = 13, 36%). Twenty-five per cent of centres (n = 9), advised no dietary restrictions when patients were well. A higher percentage of patients aged >16y rather than ≤16y were prescribed dietary restrictions: patients aged 1-10y, 67% (n = 39/58), 11-16y, 63% (n = 17/27) and >16y, 85% (n = 35/41). Patients classified as having a normal fasting tolerance increased with age from 30% in 1-10y, to 36% in 11-16y, and 58% in >16y, but it was unclear if fasting tolerance was biochemically proven. Twenty centres (56%) routinely prescribed uncooked cornstarch (UCCS) to limit overnight fasting in 47 patients regardless of their actual fasting tolerance (37%). All centres advocated an emergency regimen mainly based on glucose polymer for illness management. Although all patients were prescribed an emergency regimen for illness, use of sucrose and fructose restricted diets with UCCS supplementation varied widely. Restrictions did not relax with age. International guidelines are necessary to help direct future dietary management of FBPase deficiency.

Aim: To evaluate the status of the nutritional management of diet-treated IEM in Brazil from the perspectives of healthcare professionals, patients, and families. Methods: Data were collected through two nationwide digital questionnaires administered to healthcare professionals involved in dietary management (n = 37) and to patients and caregivers (n = 278), addressing professional training, workload, access to resources, treatment adherence, and socioeconomic factors. Results: Healthcare professionals from 20 out of the 26 Brazilian states participated, most of them female (81%) and dietitians (81%). Although more than half had over 10 years of experience, 59% considered their training insufficient to work with IEM. Only 19% reported exclusive dedication to the field, and 54% were the sole professional responsible for dietary prescriptions at their center. Weekly workload dedicated to IEM varied widely. Among the patients and families, phenylketonuria (60.4%) and glycogen storage disease (25.9%) were the most frequent conditions. Higher educational level and longer time since diagnosis were associated with a better understanding of dietary management (p < 0.05). Among patients on protein-restricted diets, most reported regular use of protein substitutes, although 92% reported poor palatability and 36% reported supply problems. Access to special low-protein foods was limited, and over half of the families reported some level of food insecurity. Conclusions: Significant systemic, logistical, and socioeconomic barriers to optimal dietary management of IEM persist in Brazil, highlighting the need for strengthened public policies, professional training, and equitable access to dietary resources.