Is fasting exercise really more fat burning? Science tells you the truth

At the moment of lifting the blanket in winter morning, there are always people who choose to run out of the door hungry, firmly believing in the "fat burning effect of fasting exercise. Double". Is there any scientific basis for the saying "30 minutes of fasting aerobic golden time" circulating in social media? Today we will use a microscope to take a look at this old topic in the fitness circle.

1. How fasting exercise affects fat burning

1. Blood sugar levels determine energy supply mode: After 8-12 hours of fasting, the body's glycogen reserves decrease by about 50%, and exercise does indeed promote the body to break down more fat for energy supply. A 2018 study in the journal Frontiers in Nutrition showed that moderate intensity exercise on an empty stomach resulted in a 20-25% increase in fat supply compared to postprandial exercise.

2. But don't rush to be happy: this "fat burning advantage" is mainly reflected during exercise. A 20-year tracking experiment conducted by the University of Bath in the UK found that the difference in total fat consumption between two groups of (fasting/non fasting) exercisers within 24 hours was less than 5%, as the body automatically regulates energy allocation during subsequent eating.

2. Hidden Costs of Fasting Exercise

1. Risk of Muscle Loss: When blood sugar and liver glycogen are insufficient, the body breaks down muscle protein and converts it into glucose. Day The Sports Science Association recommends that consuming at least 10 grams of easily absorbable protein (such as whey protein) before morning exercise can reduce the risk of muscle breakdown by up to 67%.

2. Discounted athletic performance: According to tests conducted by the Norwegian Sports Institute, the duration of high-intensity training on an empty stomach is reduced by an average of 23%, and the load of strength training is reduced by 15%. Sports that require explosive power, such as HIIT and basketball, are particularly affected.

3. Who is suitable for fasting exercise

1. Low intensity aerobic enthusiasts: Walking, jogging, cycling, and exercising on an empty stomach can indeed improve fat mobilization efficiency, but it is recommended to control it within 30 minutes.

2. Insulin sensitive population: for patients with pre diabetes or metabolic syndrome, morning fasting exercise may help improve the ability to regulate blood sugar. But it is necessary to carry quick carbon water with you to prevent hypoglycemia.

4. Smarter Fat burning Plan

1. Semi fasting Strategy: Eating a banana or whole wheat bread one hour before exercise can avoid low blood sugar without affecting fat burning efficiency. Taiwan Experiments conducted by Wan Normal University have confirmed that the fat oxidation rate in this state can reach 92% of the fasting state.

2. Time selection is more important than fasting: Cortisol naturally peaks between 6-8 in the morning, and exercise itself can burn 12-15% more fat at this time. Instead of worrying about whether or not to have breakfast, it's better to set a regular morning exercise circadian rhythm. Ultimately, the effect of exercise is a long-term accumulation process. Instead of pursuing the marginal benefits of fasting, it's better to choose exercise routines and dietary rhythms that can help you persist for longer periods of time. After waking up tomorrow, should I have a cup of honey water first or start practicing directly? Now you have a more scientific decision-making basis.