The kidneys filter out excess waste that your body does not use. The four main food culprits that can harm the kidney are phosphorous, protein, sodium, and potassium. Reducing some of these foods from your diet, not eliminating without a doctor order, can help the kidneys from getting further damage. Again, I must restate I am not giving advice, seek the advice of your doctor, everyone is different and you may have other illnesses that you have to be even more careful about your diet than I do. Your body needs all of these things, but you might need less, or more, than someone else.
I will start with the easiest one first, Phosphorous. Phosphorous is found in dark colas, and meat, mostly. Those are the two largest sources of Phosphorous. I have already given up Pepsi, and refuse to drink any dark colas, even diet. Meat, my portions are down to one to two servings a day. A serving of meat is a piece that will fit in the palm of your hand. If you are like me, and millions of other Americans, you probably are, or were eating 3-4 times the serving size per meal. I can't forget dairy. I quit dairy at least a year ago, maybe more, so I almost forgot to mention that one.
Sodium, imo, is the most difficult to control. We over eat salt at such an excessive rate in this country, it is no surprise that we have so many chronic illnesses. Salt is in everything, and I mean everything. What I do for salt is I read labels, all labels. Sodium has to be on there, even if it is zero, it is the law. If a serving size of anything has more than 140mg of Sodium in it, I don't eat it, period. We do not cook with salt, and if I add it, I add it to my own food in little pinches. I have learned to enjoy other spices besides salt, and if you have a kidney issue you should not be using Sea Salt. Also, if you have a kidney issue salt substitutes contain very high levels of potassium, so be very careful. Drinks, also have sodium in them. Water is best obviously, but since I get very bored of just water, I use Ocean Spray juice blends only. They are low in sodium, and use no preservatives or added chemicals.
Potassium is next. I love potassium rich foods, tomatoes, oranges and bananas. I no longer eat those things, or if I do in very small amounts even less than a portion size would be. Since having a low potassium level is just as dangerous as a high potassium, you really have to be careful when messing with this one. Potatoes too, another favorite, are high in potassium, but you can leach them before using them. I do this every time I cook them now. Leaching involves, peeling and soaking them for hours in water, before cooking them. When you do cook them, you have to drain the water and cook in new water. Below I will share two websites that I love on nutrition for CKD.
Last but not least is protein. Your body needs protein, but we Americans eat way too much of it, and some people eat enormous amounts to build muscle mass. Again, meat, dairy, and legumes are the main sources of high protein foods. For this one I do similar to Phosphorous, mostly avoiding red meat, and smaller portion sizes. I do similar to Sodium in that if it is more than 140mg per serving, I try to avoid it, or get the portion size down to the amount I just mentioned. Sometimes this means I am eating very little meat, but I would rather have a tiny piece of steak, than no steak at all.
You need Iron, Vitamin D, and Calcium all which the foods I mentioned are good sources of. Your physician may recommend you take a supplement if you have CKD to be sure your levels do not go too low. Iron is a hard one for me, because I don't want to take oral iron due to risk of constipation. So, since I am not diabetic I eat cereal at least twice a week, since most cereals are fortified with Iron, giving me a good safe source for my needs.
Eating out is very difficult, and I can speak to that first hand. One of the things my family very much enjoys is eating out. I would say we eat out at least once a week. I have had to majorly change my eating habits when eating out. I have informed my family I will no longer eat McDonalds, or any other fast food, and if at a restaurant I always have a salad, and bread, then I pick the best dish to fit all the above and try to eat only a quarter to half of it, and bring the rest home. I can tell you, if you have CKD, and don't want to be on dialysis, that is my goal to not be on dialysis, then learn to cook, Pre packaged foods, fast foods, snacks and a lot of breads are all high is sodium and full of preservatives all which are bad for the kidneys.
These are two of my favorite websites for CKD. I am still newly diagnosed, so I am always looking for good reputable resources for myself. Davita, offers a great menu and recipe planner for CKD. I love it.
National Kidney Foundation