In connection with the topic of weight loss, the term "calorie cutting" is often used. But what does that mean exactly? And why is it particularly important to keep your body weight in the right range when you have kidney disease, are on dialysis or before and after a kidney transplant? You can find the answers to these questions in this blog article.
You probably know that a normal body weight has a positive influence on your health and can protect your cardiovascular system from diseases such as heart attacks. But your kidneys also benefit from a healthy weight. Let's take a look at why and what you can do about it.
How is body weight classified?
To be able to compare the weight of people of different sizes, the so-called body mass index (=BMI) was introduced. Using a formula, the weight and the body size are put in relation to each other.
On the basis of the BMI, your body weight can be divided into different groups:
Ideally, your BMI should be in a range between 18.5 and 24.9 - because as always, the golden mean is the goal. Both too much weight and being underweight put extra stress on your body.
What effect can obesity have on my kidney(s)?
Obesity especially has a negative impact on many different functions in your body. Your metabolism, for example, suffers from too much body mass, which can lead to diabetes in the long term. In the course of time, your blood vessels will also suffer from increasing calcification, which means that all your organs will suffer from the excess weight - including your kidneys. If you have kidney disease, you have probably heard your doctor talk about the progression of your kidney failure. This refers to the progressive decline in your kidney function. Being overweight can accelerate the progressive loss of your kidney function. We don't want to take away any pleasure of eating food or point any fingers with this article. We just want you to know how important a healthy weight is to protect your kidney in the long run.
Of course, the same goes for transplanted kidneys. After all, your new kidney should last as long as possible, keeping your blood clean and your body in balance. Since many studies have now shown that being overweight both before and after transplantation has a negative impact on the life of your donor kidney, weight is often taken into account even before surgery. In some cases, a BMI below 30 is required to be approved for transplantation. In addition to the effects on your kidney function, your weight also plays a decisive role in your wound healing. If your weight is in the upper range, complications during the healing process after the operation are significantly less likely. This is yet another reason to reach your ideal weight through conscious nutrition and exercise. In the following sections, you will find out how calorie counting can help you achieve this goal.
What are calories?
For all our body functions, we need energy, which we largely take in through our food. There are three main groups of energy sources in our diet: Carbohydrates (consisting of sugar molecules), proteins and fats. To describe the amount of energy released by a food, the unit calories (or kilocalories) is used. Calories indicate how much energy is contained in food.
How many calories do I need in a day?
How many calories a person needs per day is very individual and depends on many different factors. If you do a lot of sports on a day, your body naturally consumes more energy or calories than on a day when you lie relaxed on the couch. But your age and size also play an important role in your energy needs.
The amount of energy you need to maintain your major body functions while you sleep - for example, your breathing and body temperature - is also called your basal metabolic rate.
But since you don't usually just sleep all day, the energy needed for your daily activities or exercise is added to your basal metabolic rate. This amount of energy is also called active metabolic rate.
The energy you need for a whole day is therefore made up of your basal metabolic rate and your active metabolic rate. That's why this value is also called total metabolic rate.
That was quite a lot of terms. For a better overview, we have summarized them for you in the following table:
If you consume exactly the amount of energy or calories in your diet that corresponds to your total metabolic rate, your body weight will usually remain pretty much the same. In other words, if you take in exactly as much energy as you also consume, there will be no excess or lack of energy that would need to be compensated. If you supply your body with more energy, i.e. calories, than you consume during the day, your body builds up a stock. Some of it is stored in your muscles and liver. A large part, however, is stored in the form of fat. If we take the thought experiment further, it means that if you burn more energy than you take in, you will lose weight.
Recommendations for kidney disease
KDIGO (=Kidney Disease: Improving Global Outcomes) guidelines specifically address people with kidney disease. For example, they recommend that kidney transplant patients with a BMI between 18.5 and 30 should eat between 25 and 35 kcal/kg of body weight every day to help maintain their weight. If your BMI is in this range, you can easily calculate your daily energy needs by multiplying your body weight by the 25 or 35 kcal. If your BMI is above 30, weight loss is recommended. To achieve this, you should eat 500 to 1,000 kcal less per day than the calculated 25 to 35 kcal per kilogram of body weight. If you have a kidney disease, your recommended calorie intake is 20 to 25 kcal per kilogram of body weight per day to maintain your weight. However, since this is only a guideline and many other factors play a role, it is best to determine your individual daily energy requirements with your treating medical team. They are the experts in this area and can take other factors into consideration.
How does calorie counting help me maintain or reach my ideal weight?
As you already know, the energy you don't use is stored in your body - mainly in the form of fat. If you want to maintain your weight, you should eat exactly as many calories as you burn per day (=total metabolic rate). This also means that if your goal is to lose weight, you need to eat fewer calories than your body burns. In this case the body is forced to use its own energy reserves and it draws upon the fat stored in various areas of your body.
Once you have calculated your total metabolic rate, it makes sense to keep track of how many calories you consume per day, at least over a certain period of time. As a starting point, you can try and track your calories for a week. This way you can easily find out if you are taking in more calories than you consume. But how do you find out how many calories are in your food? You'll find out in the next section.
How many calories are in my food?
If you want to start documenting your daily calorie intake, you first need to find out how many calories your food contains.
Manufacturers are required to indicate on all foods, in the form of tables, how many calories are contained in the food item. Most often, this information refers to 100 g of this food. And that brings us to a somewhat annoying part. In order to be able to determine the amount of calories more or less accurately, it makes sense to weigh out your meals, especially in the beginning. This way you will quickly get a feeling for the appropriate amounts. Once you have a better idea of quantities, you don't have to weight each time.
If you want to determine the calorie amount of a whole dish - for example pasta with pesto - then you determine the amount of pasta and the amount of pesto you use. Then, to figure out the corresponding calorie count, you divide the weighed amount in grams by 100 (if the calorie information is based on 100 grams) and multiply that number by the calories given.
To make the whole thing easier to understand, here's another calculation example: 100 g of cooked whole-grain pasta contain about 140 kcal, 100 g of pesto contain about 520 kcal. For a portion of pasta with pesto, about 250 g of cooked whole-grain pasta and 40 g of pesto are used. The calculation for the amount of calories is therefore:
250 g whole wheat pasta / 100 g = 2.5
2.5 x 140 kcal = 350 kcal
40 g pesto / 100 g = 0.4
0.4 x 520 kcal = 208 kcal
Calorie amount for 1 serving of pasta with pesto: 350 kcal + 208 kcal = 558 kcal
That means if you eat one serving of pasta with pesto, that equals about 558 kcal
If all this is too complicated for you, you can easily look up the calorie content of your food in the Mizu app.
Here you can select different ingredients and specify the respective amount you eat. The app will then automatically calculate for you roughly how many calories that equates to.
At this point, a very important note: Drinks such as juices or soft drinks also contain calories that you should not ignore. Unless, of course, you mainly drink water. By adding a few squirts of lemon juice, you can spice up the taste without any sugar or calories.
What else should you watch out for?
It is great if you get an overview of your daily energy intake by counting calories! But not only the amount is important, but also what you eat. A balanced and healthy diet is still especially important. In connection with kidney disease and after kidney transplantation, the Mediterranean diet is particularly recommended. Central components are vegetables, fish instead of meat and vegetable fats such as olive oil instead of animal fats. By doing a lot of your own cooking, you won't fall for hidden sugars in convenience foods. If you want to know exactly what the Mediterranean diet entails, check out the Mizu app for articles on the Mediterranean diet.
In addition, you can naturally help your body lose weight by exercising. More movement also means a higher energy consumption. It is recommended to exercise at least five times a week, for 30 minutes, in a way that makes you sweat easily. If you have just had a kidney transplant, you should of course only start exercising after consulting with your treating physician. The important thing here is to slowly get used to the strain again. The best way to do this is to draw up a plan with your medical team and decide together which types of sport are suitable.
Now you know the most important basics about weight, nutrition and calorie counting and can start immediately. But please do not put yourself under pressure. It is perfectly normal that it takes a few days to get started. However, you will soon find that you gradually develop a feeling for the food and its nutritional values. If you are having a hard time with the whole topic, just talk openly about it with your doctor or nutritionist. They can certainly give you many valuable tips on how you can better integrate calorie counting into your daily routine.
