*3.1. Life Style Intervention*

Patients with obesity, particularly those with markers of renal injury (albuminuria/ tubular markers or eGFR < 60 mL/min/1.73 m2), need to be encouraged to lose weight through a combination of diet and physical exercise. If addressed early, a low-calorie diet, with or without physical exercise, is able to reduce albuminuria with a decrease being proportional to the reduced weight. Weight loss achieved through a combination of diet and exercise has also had beneficial effects on the reduction in urinary protein excretion. After diet introduction, it is possible to observe UAE reduction in a few weeks. In a control trial, which lasted for five months, a 4% weight reduction decreased proteinuria in around 50% of subjects [90]. However, data on slowing the progression to CKD were less documented due to difficulties in assessing the outcomes [91,92] and the short-term duration of the studies [55].

A low-calorie diet with salt restriction is recommended since it can contribute to BP reduction [55]. Further salt intake reduction should be implemented if proteinuria is present. Addition of fibre in the diet promotes growth of short-chain fatty acid producing bacteria that have been demonstrated to reduce all-cause mortality in CKD [93] and there seem to be promising results regarding preclinical CKD risk [94]. A high-protein diet is not recommended since it increases GFR and UAE.

A recent manuscript reviewed the randomized clinical trials of lifestyle intervention in patients with CKD [55]. Diet intervention with low-calorie and salt restriction reduce weight and albuminuria; however, no convincing data exist for other specific dietary pattern such as low fat, low carbohydrate, or a Mediterranean diet. Studies performed on the impact of physical exercise demonstrated a reduction in BP, BMI, and improvement in exercise capacity and quality of life; however, no reduction in albuminuria was observed. The limitation of losing weight with lifestyle is that the maximal reduction achieved is 3 to 4% and the maintenance overtime is poor, therefore other additional actions need to be implemented.
