Post-delivery (up to 1 year from birth) Stop nutritional supplement Recruitment Self-referral of interested women who hear through public advertisement, social media, hospitals and primary care Exclusion: known DM (type 1 or 2), pregnant, lactating, require assisted conception (except those requiring only clomiphene or letrozole), on oral or implanted contraceptive, metformin, systemic steroids, anti-convulsant medication or treatment for HIV, Hepatitis B or C in past month, known serious food allergy Identification of participants planning to conceive in the next 6 months; 18 - 38 years old; living in Southampton, Singapore, Auckland Preconception PCV1: n = 1800; OGTT and metabolic phenotyping, questionnaires (N, L, OH, MH, FH, PA, M, S), anthropometry, BIA, BP, biosampling (~,@,#,$) Withdrawal: participant choice, loss to follow-up, <60% compliant, adverse reaction, medical reasons Randomisation (stratified by site and ethnicity) Control drink, n = 900 Intervention drink, n = 900 Preconception OGTT results from PCV1 known NGT IFG (6.0-6.9 mmol/L) or IGT (7.8-11.0 mmol/L): given advice to maintain a healthy weight, eat well and be active. Antenatal care team will be informed of result when participant conceives.   Withdrawal: new type 2 DM (Fasting glucose >7.0 mmol/L or 2h post glucose > 11.1 mmol/L) Withdrawal: pregnancy before or at PCV2 PCV2 (21-42 days after PCV1): questionnaires (MSH), biosampling (~,@,#,$,^), DXA PC Resupply visits (for 12 months from PCV2) Withdrawal: not pregnant after 12 months from PCV2 Pregnancy PGV1 (7 weeks): n = 600; USS, questionnaires (N, MSH, MTH, PA, M, S), anthropometry, BIA, BP, actigraphy, biosampling (~,@,#,$) Withdrawal: pregnancy loss, ectopic or multiple pregnancy, perinatal demise PGV2 (12 weeks): USS, biosample (@,#,$,^) collection Paternal visit: n = 600; questionnaires (GH, MH, FH, L, M), anthropometry, BP, biosampling (~,@,#,$) PGV3 (20 weeks): USS, questionnaires (N, MTH, PA, S), anthropometry, BIA, BP, biosampling (@,#,$) PGV4 (28 weeks): OGTT; questionnaires (MTH, IIF, L, M, S), biosampling (~,@,#,$) Primary outcome: OGTT plasma glucose - fasting, 1h and 2h post-glucose load NGT GDM (treatment according to local guidelines) PGV5 (34 weeks): USS, questionnaires (N, MTH, PA, M, S), anthropometry, BIA, BP, biosampling (@,#,$,^,*) Post-delivery (up to 1 year from birth) BIRTH: n = 550; placenta, cord and cord blood sampling, subcutaneous fat (subset); antenatal and delivery outcomes Stop nutritional supplement Mother: questionnaires (MTH, N, MH) Infant: anthropometry, biosampling (@,$,^) PDV1 (1 week) Mother: questionnaires (BM), biosampling (^,) Infant: questionnaires (IFH), anthropometry, PeaPod, DXA (subset), biosampling ($) PDV2 (3 weeks) Mother: questionnaires (BM, N, M), biosampling ($,) Infant: questionnaires (IFH, S), anthropometry, biosampling ($,^) PDV3 (6 weeks) Mother: questionnaires (BM, N, MH, S), BP, BIA, biosampling ($,) Infant: questionnaires (IFH, S), anthropometry, PeaPod, BIA, biosampling (@,$) PDV4 (3 months) Mother: questionnaires (BM, N, MH, S), biosampling ($,) Infant: questionnaires (IFH, BEBQ, S), anthropometry, biosampling (@,$,^) PDV5 (6 months) Mother: OGTT, questionnaires (GH, N, M, S), anthropometry, BIA, BP, biosampling (@,#,$), DXA, skin prick test Infant: questionnaires (IFH), anthropometry, PeaPod, BIA, biosampling (@,$), skin prick test PDV6 (12 months) Mother: biosampling ($) Infant: questionnaires (IFH), anthropometry, BIA, biosampling (@,$), skin prick test