Zone diet

, medical expert
Last reviewed: 14.08.2021

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Barry Sire, Ph.D., author of Enter the Zone and Mastering the Zone, claims that a high-carbohydrate diet worsens athletic performance and promotes completeness. The author considers carbohydrates and insulin as harmful substances and recommends a complex diet that limits carbohydrate intake. Barry Sire advises eating at each meal 40% of calories in the form of carbohydrates, 30% - in the form of proteins and 30% - in the form of fats.

It is assumed that to achieve maximum performance athletes should be guided by a zonal diet, which probably contributes to optimal sports performance by changing the production of eicosanoids in such a way that the body produces more "good" ecozanoids than "bad" ones. Barry Sire claims that eicosanoids are the most potent hormones and control all physiological functions.

Supporters of the zonal diet recommend bordering the consumption of carbohydrates, so that the body does not produce too much insulin, since its high levels increase the production of "bad" eicosanoids. "Bad" eicosanoids may worsen athletic performance, reducing oxygen transfer to cells, lowering blood glucose levels and making it difficult for the body to use chi. According to Barry Sire, insulin also: will contribute to obesity, because it causes the accumulation of carbohydrates in the form of fat.

It is suggested that the protein in the zonal diet increases the level of glycogen and helps to increase the production of "good" eicosanoids, counteracting the effect of insulin. These eicosanoids are likely to enhance endurance, increasing the transfer of oxygen to the cells, facilitating the utilization of stored fat and maintaining the level of glucose in the blood.

Such information, outlined in scientific language, should intimidate athletes. However, the scientific basis of such a diet can be completely criticized. Eicosanoids do not cause disease - they are biologically active, hormone-like compounds, known as prostaglandins, thromboxanes and -eicotrienes. Eicosanoids are involved in regulating inflammation, coagulation reactions and immune system activity. The statement that eicosanoids are omnipotent, groundless, the physiology of the body is not so simple. In addition, there is no evidence that insulin produces "bad" eicosanoids, and glucagon is "good." In the literature on nutrition and biochemistry, there is no information on metabolic pathways linking diet, insulin, glucagon and eicosanoids. The idea that this diet (or any other) completely regulates the production of insulin and glucagon is not endocrinologically confirmed, and "the statement that insulin and glucagon control the production of eicosanoids is not confirmed biochemically." Finally, the opinion that eicosanoids control all physiological functions ( including athletic performance), not only unfoundedly, but also overly simplifies complex physiological processes.

Carbohydrates are needed for athletes to keep their work at a high level. In contrast to the claims of the Zone Books, the consumption of high-carbohydrate foods 1-4 hours before the load improves through increased blood glucose levels and replenishment of glycogen stores. Consuming carbohydrates during a one-hour and longer-lasting exercise increases endurance by supplying the muscles with glucose, when muscle glycogen stores are depleted. Consumption of carbohydrates immediately after intensive training increases the supply of muscle glycogen.

The body weight depends on how many calories are absorbed in comparison with how many "burned" them. There is also no evidence that insulin is the cause of the fullness of people.

The zonal diet is simply low-energy. Zone books try to disguise this, forcing people to consider protein and carbohydrate components instead of kilocalories. Although Sire does not focus on energy absorption, the zonal diet provides only about 1200 kcal (120 grams of carbohydrates) for the average woman and 1,700 kcal per day (170 carbohydrates) for the average male. The diet is also inadequate for thiamine, pyridoxine, magnesium, copper and chromium.

Zone diet does not increase the ability to "burn" fat during exercise. The best way for athletes to increase their ability to "burn" fat is to continue training. With regard to the gradual loss of fat, it occurs as a result of physical exertion, when a kilocalorie "burns" more than it does with food, and not a special dietary diet.

Dangers of zonal diet:

  • Inadequacy of kilocalories (approximately 1,700 for men and 1,200 for women)
  • Inadequate amounts of dietary carbohydrates (approximately 170 g for men and 120 g for women)
  • Inadequacy of food elements (thiamine, pyridoxine, magnesium, copper and chromium)
  • A misconception that a zonal diet will improve performance

And, finally, athletes can not train or compete for a long time with such a low-energy, low-carb diet. Athletes require adequate calories and carbohydrates to maintain glycogen stores in muscle tissue. Those who adhere to the zonal diet, as a result will be on the verge of starvation and poor performance.

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