BRRIDE 2 - Breast Risk Reduction Intermittent Diet Evaluation

INTERVENTION: 1. Daily energy restriction, A daily 25% energy restricted Mediterranean diet ( 1500kcal/day) for seven days/week which includes healthy fats, protein foods, low fat dairy, fruit and vegetables and high fibre carbohydrates and allows up to 10 units of alcohol per week 2. Intermittent energy restriction, a low carbohydrate energy restricted diet (600 kcal, <50g carbohydrate, 50 g protein day) for two consecutive days followed by an 1900 kcal mediterranean type diet for the remaining five days of the week. Each of the two low carbohydrate 600 kcal energy restricted days includes; 300g of lean protein foods e.g. lean meat, fish, eggs, tofu, quorn, textured vegetable protein, three portions of low fat dairy foods, five portions of low carbohydrate vegetables; one portion of low carbohydrate CONDITION: Topic: Cancer; Subtopic: Breast Cancer; Disease: Breast ; Cancer PRIMARY OUTCOME: 1. Image determined hepatic fat fraction and lipid types (MRS); 2. Insulin resistance using modelling of insulin, glucose and Cpeptide measurements during an Oral Glucose Tolerance Test (OGTT); ; All measured at baseline and after following diet for 8 weeks.; ; SECONDARY OUTCOME: 1. Body mass and composition: total body fat, visceral and subcutaneous fat (MRS).; 2. Intramyocellular fat fraction (MRS) a predictor of systemic insulin resistance; 3. Pancreatic fat fraction and lipid types (MRS); 4. L3 skeletal muscle area using MR imaging – an indicator of sarcopenia and lean body mass; 5. Markers of breast cancer risk. Inflammatory markers; IL6, adipokines: fasting adiponectin and leptin, IGF1; 6. Fasting lipid profile. i.e. total low density lipoprotein (LDL) and high density lipoprotein (HDL) and triglceride linked to risk of breast cancer44 and cardiovascular disease; 7. Resting energy expenditure (Fitmate GS portable desktop indirect calorimeter (Cosmed, Rome Italy) .; We will also assess simple clinic body fat and fat free mass (bioelectrical impedence;Tanita 180) and anthropometric measurements (waist, hip and bust circumference); ; All measured at baseline and after following diet for 8 weeks.; ; INCLUSION CRITERIA: 1. Family history of breast cancer (lifetime risk >1 in 6) 2. Premenopausal aged >30‐45 years 3. Body mass index 30‐45 kg/m2. 4. Nonsmoker 5. Sedentary (< 40 minutes moderate exercise per week)