While it is common knowledge that there are many health benefits to exercise, new research has shown that the level of exercise can directly impact your appetite. This article will explore why intense exercise decreases your appetite and discuss the level of training needed to achieve maximum results.
New research discovered that exercise stimulates a compound made of lactate and phenylalanine, which results in a reduced appetite.
Low-impact exercise can increase your appetite, but high-impact exercise burns calories hours after you've completed your workout and decreases your appetite.
Studies have shown that incorporating high-intensity exercise into your workout routine can increase weight loss, decrease fat, decrease appetite, lower blood pressure and heart rate, and improve blood glucose control.
Determining your fat-burning zone can help ensure you workout at a moderate to high intensity for maximum results.
The science behind hunger and exercise
Recent research has shown that a compound induced by intense exercise reduces appetite. Studies show that exercise stimulates the production of a molecule called Lac-Phe, a hybrid of two chemicals, lactate and phenylalanine. The production of Lac-Phe suppresses appetite and results in weight loss.
Studies on obese mice found that pharmacological-mediated increases in Lac-Phe reduced food intake without affecting movement or energy. When used long term, Lac-Phe decreased adiposity and body weight with improved blood sugar control.
So what are lactate and phenylalanine? Lactate, or lactic acid, is a chemical your body produces as your cells break down carbohydrates for energy. Lactate can come from any tissue in your body, but our muscle cells and red blood cells produce most of it. Our bodies produce lactate with exercise or when we use more oxygen than usual.
Phenylalanine is an essential amino acid that is found in high-protein foods. Phenylalanine plays a vital role in making proteins and important molecules like tyrosine, epinephrine, norepinephrine, and dopamine.
When you exercise, your body produces lactate. Intense workouts increase your heart rate and oxygen demands, causing your body to increase its lactate production. The increased production of lactate triggers the union of lactate and phenylalanine.
Studies on mice showed that mice given Lac-Phe had decreased appetites and decreased consumption of high-calorie food by about 30%. The decreased appetite led to decreased body weight, reduced fat, and improved blood glucose levels.
Intense workouts and appetite suppression
Studies have shown that the level of intensity of a workout directly impacts the amount of fat burned. Additional research has discovered that Lac-Phe plays an essential role as it decreases your appetite and leads to weight loss, reduced fat, and better glucose control. What is the optimal level of exercise to achieve maximum results?
What an intense workout looks like will vary between individuals. To determine your fat-burning zone, monitoring your heart rate during exercise is crucial. Your fat-burning zone is when you work out between 70–80% of your maximum heart rate.
Recommendations on exercising
The U.S. Department of Health and Human Services recommends the following exercise guidelines for adults:
- Move often. It is recommended that adults engage in regular physical activity throughout the day, rather than sitting for prolonged periods. Even small amounts of moderate-to-vigorous physical activity can provide some health benefits.
- Amount of exercise. Adults should aim for at least 150–300 minutes of moderate-intensity, 75–150 minutes of vigorous-intensity aerobic physical activity each week, or a combination of both. This should be spread throughout the week for optimal health benefits.
- More may be better. Engaging in more than 300 minutes (5 hours) of moderate-intensity physical activity per week provides additional health benefits.
- Resistance exercise. Adults should engage in muscle-strengthening activities involving all major muscle groups at least two days a week, with moderate or greater intensity, as these activities provide extra health benefits.
If your goal is to be in the fat-burning zone where your body produces more lactate and creates Lac-Phe, you will need to determine your target heart rate zone and then track your heart rate while exercising.
To determine your target heart rate zone:
- Subtract your age from 220 to get your maximum heart rate.
- Measure your resting heart rate and then calculate your heart rate reserve (HRR) by subtracting your resting heart rate from your maximum heart rate.
- Multiply your HRR by 0.7 (70%) and add your resting heart rate to this number.
- Then multiply your HRR by 0.85 (85%) and add your resting heart rate to this number.
These two numbers are your average target heart rate zone for vigorous exercise intensity.
Studies have shown that low-intensity workouts don't get your body into the fat-burning zone. You have to work out longer to burn the same number of calories from a high-intensity workout, and the fat-burning rate is lower with a lower-intensity workout. When you work out at a higher intensity, your body uses glycogen stores and quickly depletes them, forcing it to utilize its fat storage for energy during the workout.
Benefits of incorporating intense workouts
High-intensity fitness programs offer many health benefits and are designed to burn fat and build muscle quickly. These programs often include high-intensity interval training (HIIT) workouts, which are short but intense workouts. They consist of short bursts of intense exercises that last 15 seconds to four minutes and are followed by a quick recovery period and then return to additional intense exercises. Cycles in HIIT programs are repeated several times and include a variety of exercises each round that work for multiple major muscle groups in one workout.
HIIT and other high-intensity workouts burn a lot of calories in a short amount of time. Research has shown that your body continues to burn calories from your high-intensity workout hours after your workout.
In addition to the benefit of increased fat burning with high-intensity workouts, HIIT workouts can decrease blood pressure and heart rate and improve blood glucose control.
Lower-intensity workouts can increase your appetite, but higher-intensity workouts decrease your appetite. This can reduce weight, decrease fat, and better blood glucose control.
The discovery of Lac-Phe is an exciting development in weight loss research. This newly identified compound has the potential to revolutionize our understanding of appetite regulation and its implications for weight management. However, additional research is needed to determine the specific mechanisms through which Lac-Phe inhibits the hunger single and which receptors in the brain Lac-Phe targets. The discovery of Lac-Phe opens up new possibilities for developing targeted interventions and strategies to support individuals in their weight loss journeys.
- Stanford Medicine. 'Anti-hunger' molecule forms after exercise, scientists discover.
- Nature. An exercise-inducible metabolite that suppresses feeding and obesity.
- U.S. Department of Health and Human Services. About the Physical Activity Guidelines.
- Cleveland Clinic. Lactic Acid.
- National Library of Medicine. Phenylalanine.
Show all references
- UC Davis Health. High-intensity workouts can help you get fit fast, but preparation is key.
- Mayo Clinic. Exercise intensity: How to measure it.