Inclusion Criteria:  American College of Rheumatology classification criteria with pain in the groin or hip region on most days of the past month and femoral or acetabular osteophytes and joint space narrowing (superior, axial and/ or medial) on x-ray; aged 50 years or older; report history of hip pain ≥ 3months; report an average pain score of at least 4 on an 11-point numeric rating scale (anchored at 0=no pain, 10=worst pain imaginable) over the previous week; access to a device with internet connection; have a BMI >27 kg/m2; willing and able give informed consent and participate fully in the interventions and assessment procedures; have ability to weigh themselves (e.g. access to scales); pass the Exercise and Sports Science Australia stage 1 adult pre-exercise screening system or obtain general practitioner clearance for participation in the study.  Exclusion Criteria:  weight >150 kgs (due to the added complexities of additional nutritional requirements for individuals above this weight); inability to speak and read English; on waiting list for/planning back/lower limb surgery or bariatric surgery in next 12 months; previous arthroplasty on affected hip; recent hip surgery on affected hip (past 6 months); self-reported inflammatory arthritis (e.g. rheumatoid arthritis); weight loss of > 2 kg over the previous 3 months;  already actively trying to lose weight by any of the following mechanisms:  using meal replacements for weight loss being a member of a commercial weight loss program (e.g. weight watchers) receiving support from another health care professional for weight loss using any drugs prescribed to aid in weight loss using structured meal programs for weight loss such as 'Lite n' Easy'  unable to undertake ketogenic VLCD without closer medical supervision including self-reported:  diagnosis of Type 1 diabetes Type 2 diabetes requiring insulin or other medication apart from metformin warfarin use stroke or cardiac event in previous 6 months unstable cardiovascular condition fluid intake restriction renal (kidney) problems (unless clearance is obtained from GP, including GP confirmation that estimated glomerular filtration rate >30 mL/min/1.73m2) any neurological condition affecting lower limbs; pregnancy or planned pregnancy vegan dietary requirements due to complexity of delivering a nutritionally complete diet within the ketogenic diet regime.