Weight Management in CKD

OBESITY (BMI > 30) ACCELERATES CKD:

• Doubles risk of CKD progression
• Worsens proteinuria (obesity-related glomerulopathy)
• Raises BP and worsens diabetes
• Increases sleep apnoea (further BP rise)
• Worsens heart failure and CV risk
• Makes transplant assessment harder (BMI > 35 usually declined)

UNDERWEIGHT (BMI < 20) IN ADVANCED CKD:

• Often a sign of malnutrition (PEW — protein energy wasting)
• Strongly linked to death and dialysis complications
• Needs urgent dietitian assessment

The target for most people with CKD: BMI 20–28, waist < 94 cm (men) or < 80 cm (women).

Diet Fundamentals

• Calorie deficit of 500–750 kcal/day = 0.5–1 kg/week
• Renal-adapted Mediterranean diet works best
• Protein 0.8 g/kg/day (higher on dialysis = 1.2 g/kg)
• Don't slip into high-protein 'keto' diets — they worsen acidosis and proteinuria
• Avoid crash diets, juice cleanses, very low-calorie diets without medical supervision
• Mind potassium: avocado, banana, tomato, dried fruit, nuts

UK Meal Pattern

• Breakfast: porridge with cinnamon + small portion berries
• Lunch: salad with grilled chicken/tofu + olive oil dressing
• Dinner: white fish or lean meat + rice/pasta + low-K vegetables
• Snacks: rice cakes, popcorn (unsalted), apple, cucumber
• Drinks: water, black/green/herbal tea — limit fruit juice

Exercise

• 150 min moderate aerobic per week (walking, swimming, cycling)
• 2× strength training (preserves muscle during weight loss)
• Safe at all CKD stages — even on dialysis (intradialytic exercise)
• Avoid heavy contact sports if on warfarin or with AV fistula

GLP-1 AGONISTS — first-line:

• Semaglutide (Wegovy 2.4 mg / Ozempic 1 mg) — 12–15% loss
• Liraglutide (Saxenda 3 mg) — 6–8% loss
• Tirzepatide (Mounjaro) — 15–22% loss
• ALL safe in CKD at all eGFRs
• Start low, titrate over 16 weeks to manage nausea
• Available on NHS via Tier 3 weight clinic, or privately
• Watch for dehydration if vomiting — pause SGLT2/ACE if unwell

ORLISTAT (Xenical):

• Older option — fat malabsorption
• Can worsen oxalate kidney stones — avoid in stone formers
• Useful in early CKD without stone history

Not Recommended In CKD

• 'Fat burner' supplements — many contain harmful diuretics
• Slimming teas (often laxatives + low K)
• Phentermine — raises BP

BARIATRIC SURGERY can be life-changing for severe obesity + CKD:

• Eligibility: BMI > 35 with comorbidity (CKD counts) or BMI > 40
• Sleeve gastrectomy preferred over gastric bypass in CKD (less oxalate risk)
• Can reduce/reverse diabetic kidney disease in some patients
• Improves eligibility for transplant
• Mean weight loss 25–30% at 2 years

RISKS specific to CKD:

• Oxalate kidney stones (especially after bypass — sleeve is safer)
• Dehydration in early weeks
• Need lifelong vitamin and mineral supplementation
• Evidence-based multivitamin needed

NHS access: via Tier 3/4 weight management service, GP referral. Long waiting lists (1–2 years). Private cost £8,000–14,000 in UK.

In advanced CKD (stage 4, 5, dialysis), unintentional weight loss often means PROTEIN ENERGY WASTING (PEW):

• Loss of appetite from uraemia
• Inflammation
• Acidosis
• Restrictive renal diet limits choices
• Depression

IT IS DANGEROUS — doubles mortality on dialysis.

If You're Losing Weight Unintentionally

• Tell your renal team immediately
• Ask for urgent renal dietitian referral
• They may liberalise your diet, recommend high-calorie supplements (Renilon, Fresubin Renal), or treat acidosis
• Don't restrict salt/potassium so much that you can't eat
• Aim 30–35 kcal/kg/day, 1.0–1.2 g/kg protein on dialysis

NEVER assume weight loss is 'good' if you didn't try to lose it.