Are fruit juices healthy?
Many studies have shown that fruits have a beneficial effect on human metabolism. Daily fruit consumption has been found to promote weight loss and reduce the risk of long-term weight gain.
This is paradoxical because fruits are known to be rich in simple sugars (such as sucrose, glucose, and fructose). But simple sugars have been linked in countless studies to weight gain, dyslipidemia (a potentially dangerous increase in blood lipids), hypertension, cardiovascular disease, as well as cancer.
How do fruits and vegetables contribute to weight loss?
A lot of research has been done on this topic. The health-improving effect of fruits is associated with several mechanisms. The main ones are:
When eating whole fruits, sugar is released into the bloodstream more slowly - therefore, the feeling of satiety remains longer. As a result, the frequency and amount of eating decreases.
The feeling of satiety occurs as a result of biochemical processes, when various peptides are released from the intestines and other organs in response to food intake, which in turn regulate hunger and appetite.
Reduces energy/calorie intake due to the high soluble fiber content of whole fruits. Fiber creates a feeling of satiety and thus reduces uncontrolled eating (snacking).
Water-soluble fiber reacts with water in the small intestine and forms a thick gel, which in turn inhibits gastric emptying and the secretion of digestive enzymes.
The slowing down of the food digestion process means that the digestive products (carbohydrates, fat and protein) is absorbed much more slowly in the body. As a result, the receptors of the digestive tract are in longer contact with fatty acids, amino acids and sugars, which, in turn, leads to a decrease in the feeling of hunger for a longer period of time.
Gel formation also increases the amount of undigested food, which, in turn, reduces the digestibility of nutrients (energy/calorie intake).
Effects on gut microflora/microbiome
The amount of beneficial intestinal microflora increases, because an environment suitable for its development is available (substrate) in the form of undigested fruit residues.
Effects of antioxidants
It has been proven that fruits and vegetables increase the availability of phytochemicals, which, in turn, can prevent the formation of fat.
The anti-obesity effect of fruits and vegetables has been confirmed in various types of clinical trials.
The results of these studies (positive effect on body mass index (BMI), body weight, and waist circumference) are particularly important because they involved overweight or obese people and lasted for a relatively short time (in most cases only a few months).
Here, however, it should be reminded that fruit consumption is controlled during the research. That is, if you eat too much fruit, you will also take in too much sugar/calories, which will most likely turn into fat. There are many studies that show a correlation between obesity risk and increased fruit intake.
Is it healthier to eat the whole fruit or drink juice?
The research results are clear and unequivocal - regular consumption of fruit juice is associated with increased fat mass. In addition, regardless of whether you drink freshly squeezed juice or industrially produced packet/bottled juice.
Why is this happening?
After all, freshly squeezed juice contains all the same things that are in the fruits and vegetables from which it is squeezed.
Lack of fiber
While most of the beneficial phytochemicals in fresh-squeezed fruit and vegetable juice are in more or less the same proportions as in whole fruit, juices contain little or no fiber. Therefore, juice does not cause a feeling of satiety, but increases hunger.
There is also no beneficial effect of fiber on the intestinal microflora, and no gel is formed that inhibits the absorption of nutrients (calories).
Sugar is often added to fruit juices, especially industrial juices, to improve the taste and prolong their shelf life. Too much sugar - a higher risk of obesity.
To extend the shelf life of packaged and bottled juices, in addition to sugar, other substances are added to them, which probably also do not contribute to health promotion.
Liquids are able to enter the intestines much faster than solids and therefore are absorbed more quickly. Thus, fruit juice causes blood glucose and insulin levels to rise faster and to a higher level than whole fruit.
This is another reason why the risk of developing type 2 diabetes, obesity, and obesity-related diseases is higher when consuming fruit juices than when consuming whole fruits.
Glycemic index and glycemic load
Studies show that when using fruits in the diet, they make up only about a tenth of the total glycemic load. FFor example, fruits such as whole bananas, apples, and grapes account for about 3-4%, 2%, and 1% of the total glycemic load, respectively.
- Whole apples have a glycemic index of 38 ± 2*, but glycemic load 6 (120 g portion);
- The glycemic index of apple juice is 40 ± 1*, but glycemic load 11 (250 ml portion);
- Whole oranges have a glycemic index of 42 ± 3*, but glycemic load 5 (120 g portion);
- The glycemic index of orange juice is 52 ± 3*, but glycemic load 12 (250 ml portion).
*(glucose = 100)
Source: American Society for Clinical Nutrition.
One serving of whole oranges contains 3.1 g of fiber, while one serving of juice contains only 0.5 g.
Myths about industrially produced juices
Juices are generally considered healthy.
This is largely true of freshly squeezed juices, as long as we don't drink too much of them.
But what about packaged juices of industrial production? Are they really healthy?
Here are some facts to think about:
- Packaged juices can be stored for up to one year. Many people see this as an advantage, without thinking about the fact that long shelf life is achieved due to heat treatment, in which the juice loses all vitamins;
- During testing packaged juices, patulin was found in some, which indicates that low-quality fruits were used to prepare the juice;
- Juices marked "without preservatives" are "deprived" of oxygen (to extend their shelf life). Removing oxygen from fruits and vegetables reduces their quality;
- Packaged/bottled juices are usually very tasty, even tastier than freshly squeezed juices because they are flavored with artificial flavors and sugar or corn syrup;
- Packaged/bottled juices are much higher in calories because of the added sugar;
- Sometimes we choose juices with "softness", but when we check the composition of such juices on the label, it often turns out that there is very little or no fiber in them. I wonder where it has gone?
- Packaged juices contain simple carbohydrates, which immediately increases the blood glucose level, and if this glucose is not used up, it turns into fat.
It is best to eat whole fruits and vegetables.
Especially if you want to lose weight, because juices, even freshly squeezed, are much more caloric.
How many apples can you eat? And how many glasses of apple juice could you have? To get a glass of apple juice, you need to squeeze 3-4 apples. One glass of apple juice contains about 120 calories, but 1 apple contains only about 78 calories.
Proponents of drinking juice often argue that drinking juice is better than eating whole fruits and vegetables because the nutrients from the juice are more easily absorbed (those that remain).
- There are no scientific studies to support this;
- Even if this were the case, the greatest health benefits are brought by fiber contained in whole fruits and vegetables. When juicing together with fiber, other substances we need are lost, for example, antioxidants, which are naturally associated with fruit fiber.
Depending on the type of juicer, up to 90% of the fiber is removed during juicing. Some soluble fiber will remain, but most of it will be removed.
Many studies have found a link between fruit juice consumption and increased BMI, but whole fruits and vegetables have been linked to obesity in only a few cases, mainly as a result of excessive consumption.
Fresh fruit consumption in relation to incident diabetes and diabetic vascular complications
Paradoxical Effects of Fruit on Obesity
Health Benefits of Fruits and Vegetables
Excessive fruit consumption during the second trimester is associated with increased likelihood of gestational diabetes mellitus
Evaluation of Fruit Intake and its Relation to Body Mass Index of Adolescents
Let them eat fruit! The effect of fruit and vegetable consumption on psychological well-being in young adults
Fresh Fruit Consumption and Major Cardiovascular Disease in China
Fruit consumption and risk of type 2 diabetes
The effect of fruit in different forms on energy intake and satiety at a meal
Intake of whole apples or clear apple juice has contrasting effects on plasma lipids in healthy volunteers
Polyphenols as dietary fiber associated compounds. Comparative study on in vivo and in vitro properties
Nonextractable polyphenols, usually ignored, are the major part of dietary polyphenols
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