Yes, nutrition is very important in renal failure, especially protein intake. Following P. Jungers (Necker Hospital, Paris), it must be of the order of 0.7 g / kg body weight / day if creatinine clearance is  60 ml/min/1.73m2. Not reduce protein intake too much especially in the elderly and ensure that abumine does not drop below 35 g / L. A supplement of vitamins, Ca, the control of the amount of water and ingested Na should be considered depending on the circumstances and the type of kidney disease. 

For a recent development, see the clinical pratice guideline for evaluation and menagement of chronic kidney disease (KDIGO 2012)

www.kidney-international.org

The MDRD study was a landmark trial set up to prove the importance of dietary protein in slowing the progression of kidney failure.  This had been shown in animal models but human studies were not so clear.The Results were surprising aslow protein  diet had no impact on rate of loss of GFR. And more over , the very low protein deit was associated with higher mortality without impact on renal progression

american journal for kidney diseases,(AJKD),suggested no limitation of dietory protein intake for the pregnancy patients with DM and CKD stage 5,they have not included in specific treatment studies.And is there any lack of  evidences  in clinical trials or studies for  general population with DM and CKD stages or any research papers published?

That's right, in current practice, nephrologists will not advise a restricted diet intake of proteins; according to them, the patients naturally eat less meat (natural disgust). This avoids denutrition. A restriction is only recommended if the patient has clearly a diet with excess proteins. The guidelines I gave you dated a few years, they are no longer applicable. Sorry for the misinformation.

Nutrition is fundamental to:

a) avoid malnutrition and MIA syndrome

b) Give adequate caloric support

c) Limit unuseful proteic intake

d) don't give phoshorous