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Fasted Cardio vs. Non-Fasted Cardio for Most Fats Loss

An article published in the New York Times on December 3, 2019 reported that “Cyclists who peddle on an empty stomach have burned twice as much fat.”

In the past, it has been reported in the scientific literature that aerobic exercise accelerates the loss of body fat after an overnight fast. Research has shown that low glycogen and insulin levels from overnight fasting cause your body to shift fuel away from carbohydrates, allowing greater mobilization of stored fat that is burned for energy. This strategy is basically supposed to help you become a fat burning machine.

An article published in the New York Times on December 3, 2019 reported that “Cyclists Peddling On An Empty Stomach Burned Twice As Much Fat.” This study, featured in the Times article, was published in the Journal of Clinical Endocrinology and Metabolism published. The study found that exercising on an empty stomach before breakfast can lower muscle fat!

The study reported that the researchers’ goal was to “assess the acute and chronic effects of exercise performed before or after nutrient intake on whole body lipid utilization and intramuscular activity and postprandial glucose metabolism”.

In a six-week, randomized, controlled crossover study, researchers from the University of Bath, England recruited 30 overweight, sedentary men. The researchers divided the men into three groups, one as a control group and the other two groups, who rode a stationary bike three times a week and monitored the subjects’ heart rate and fat burning at a moderate pace. One training group also drank a vanilla-flavored shake (without further breakfast) two hours before their ride, while the other group swallowed a similar-tasting placebo drink that contained water, flavorings, and no calories. In other words, the placebo group drove on an empty stomach but didn’t know.

However, the drivers who pedaled on an empty stomach had burned about twice as much fat on each trip as the men who consumed the shake first. The riders had all burned roughly the same amount of calories pedaling, but more of those calories came from fat if the men didn’t eat first.

Lose muscle fat

According to Javier Gonzalez, lead researcher on the study, said, “The reasons for this extra metabolic boost are complex, but most likely involve losing muscle fat. Sober drivers’ bodies had to rely on internal stores of energy to get fuel, including fat, from their muscles. (Interestingly, the sober drivers did not feel that their training was more strenuous than that of the other group, according to everyone’s subjective assessment of the effort.) ”

The results of this study in the Journal of Clinical Endocrinology and Metabolism confirm the benefits of pre-breakfast cardio fasting for maximum fat loss! If you have a meal or carbohydrates before a workout, you increase insulin levels, which improves fat storage and inhibits fat mobilization, oxidation, and fat burning. You don’t want to release insulin before cardio if you’re looking to burn more fat. Fasting on an empty stomach before cardio allows your body to switch fuel from burning glucose to burning fat. Research shows that empty cardio before breakfast does not result in greater muscle loss than fed cardio.

A June 1, 2018 study published in the International Journal of Exercise Science reported that fasting 10 hours before weight training improved fat oxidation and burning. There are few studies that have examined the long-term effects of fasting cardio on body composition. The British Journal of Nutrition compared a morning run to an early breakfast or fasting state. Without breakfast, 20% more fat was burned! Another research found that cardiovascular diet or fasting did not affect the amount of fat you lose (J Int Soc Sports Nutr, 2014). What research should we believe?

Scientific research has shown that empty cardio could be an exciting and promising method for weight loss, fat loss, weight control, and metabolic health. Research shows that for someone with stubborn body fat, as well as someone who is lean and wants to work off, doing an empty cardio before breakfast can improve more belly fat and improve intramuscular fat burning!

“The fat that makes you thin”

A study published January 7, 2021 in the Journal of the International Society of Sports Nutrition reported that consuming caffeine 30 minutes before exercise increased whole body fat oxidation and fat burning during aerobic exercise.

Caffeine is a powerful central nervous system stimulant that has been shown to increase energy, mental alertness, focus, and exercise performance. It can also reduce appetite and boost metabolism and fat burning. Research has shown that just 100 milligrams of caffeine, the amount in a cup of coffee, can improve the thermogenesis of brown adipose tissue (BAT) and increase energy consumption.

The popular belief that all body fat is bad is currently being questioned due to the recent discovery in humans of another type of fat known as brown fat (BAT). This type of body fat can actually burn energy in the form of heat through a process called thermogenesis that can ultimately reduce all body fat.

The body has two forms of fat: white fat, or unwanted fat, which can be just under the skin, and brown fat, which is often found in the shoulder blade area or on the neck. Unlike white fat, brown fat is the good fat as it can help burn more calories. The more brown fat you have, the more calories you burn. Brown fat is often referred to as “the fat that makes you thin”.

Brown fat is packed with mitochondria loaded with UCP-1, the protein that decouples fat burning from ATP (energy) production instead of converting energy into heat through thermogenesis, effectively making the mitochondria the cell’s furnace . The advent of brown fat as a readily available fat burning stove is revolutionary, but like any fire, it requires the right lighting materials. The ability to slim down by producing extra brown fat or to increase the activity of existing brown fat is a promising way to burn fat and lose weight.

Several breakthrough discoveries and approaches to improving the function of brown fat are being explored with great excitement in major research centers and universities around the world. Research on brown fat is a hot topic today.


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9. Ramírez-Maldonado M, Jurado-Fasoli L, Del Coso J, Ruiz R, Amaro-Gahete FJ. Caffeine Increases Maximum Fat Oxidation During a Graduated Exercise Test: Is There a Time-of-Day Variation? J Int Soc Sports Nutr. January 7, 2021; 18 (1): 5. doi: 10.1186 / s12970-020-00400-6. PMID: 33413459; PMCID: PMC7792284.

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