Most of the studies found suppression of appetite occurred at exercise intensities greater than ~70% of aerobic capacity. Lactate produced during high-intensity exercise is suggested to suppress appetite by suppressing ghrelin levels.
IS EXERCISE AN APPETITE SUPPRESSANT (WHAT SCIENCE SAYS!)SUMMARY
- The question of whether is exercise an appetite suppressant is hotly debated.
- Higher intensity exercise is associated with greater appetite suppression.
- Lactate levels produced during exercise can suppress the hunger-stimulating hormone ghrelin.
Introduction
Acute exercise intensities have a mixed impact on appetite; some studies show an increase in appetite, while others show a decrease.(1) For instance, exercise caused subjects’ energy intake to range from -243.3 calories to +278.5 calories. In the study, 56% of the subjects ate the same or less, while 38% ate more after exercising.(2)
Some individuals suggest that higher intensity exercises might make some people want to eat more. If you experience hunger after a workout, you’re not the only one. You can explore discussions on Reddit where people discuss feeling constantly hungry after starting their workout routines.
Higher glycogen replacement and carbohydrate oxidation (i.e., the usage of carbohydrates during exercise) correlate with the post-exercise energy intake response.
One study discovered a positive correlation between the amount of carbs burned and the number of calories consumed after exercise.(2)
WHY AM I NOT HUNGRY AFTER WORKING OUT
Exercise intensity seems to have a more profound impact than exercise duration.(3) There is a dose-dependent response between exercise intensity and appetite suppression (i.e., higher exercise intensity led to a greater suppression in appetite).(4)
Studies have found that higher lactate levels seem to play an important role in the suppression of appetite. Sodium bicarbonate, which allows for a stronger acid-base buffer in the blood during intense exercise, allows for more lactate.
STARTING EXERCISE AND LOST APPETITE…ITS LACTATE!
Researchers found that when subjects were administered sodium bicarbonate, their lactate levels were higher than the control group, but also their ghrelin levels were suppressed (~25% lower than the control group). Overall appetite was lower than well after exercise.(5) This suggests a relationship between increasing lactate and appetite suppression after exercise.
WHY AM I HUNGRY AFTER I WORKOUT?/EXERCISE KILLS MY APPETITE
Many people have wondered does exercise increase hunger or if it is all in their head. Studies have found that full-body resistance exercise protocols (i.e., leg press, bench press, T bar row, leg extension, leg curls, and bicep curls) produce higher lactate levels and greater appetite suppression than an upper body splits (i.e., bench press and T-Bar rows) and lower body exercises (leg press, leg extensions, and leg curls) that produced lower levels of lactate.(6)
WHY AM I SO HUNGRY AFTER EXERCISE? (WHAT SCIENCE SAYS YOU CAN DO ABOUT IT!)
Studies have found that High-intensity exercise has been shown to suppress hunger and the hunger-stimulating hormone ghrelin after exercise. A 2014 meta-analysis of 75 studies, including 241 subjects, found that acute exercise had a small to moderate effect in reducing hunger-stimulating hormones (i.e., ghrelin, PYY, GLP-1, etc.).
Thus, long-term exercise can have a beneficial effect on reducing energy intake after exercise.(7) It has been found that exercises that involve large muscle groups result in a large metabolic demand and can result in a stronger suppression of appetite than lower-intensity exercise.
For example, researchers compared different exercise intensity levels and their effects on appetite-suppressing hormones. Subjects were assigned to moderate intensity (65% of aerobic capacity), vigorous intensity (85% of aerobic capacity), and all-out sprint cycling (100% aerobic capacity).
IS EXERCISE AN APPETITE SUPPRESSANT? THAT DEPENDS…
Appetite was suppressed after exercise in all the groups, but the vigorous and all-out sprint groups had greater appetite suppression.(8) Another finding was that higher blood lactate in the vigorous and all-out sprint exercises correlates with the suppressed levels of the hunger-stimulating hormone ghrelin.
Most studies found that appetite suppression occurred at exercise intensities greater than ~70% of aerobic capacity. (2, 9, 10) Lactate produced during high-intensity exercise is suggested to suppress appetite by suppressing ghrelin levels.(4)
Resistance exercise seems to provide a superior effect for reducing post-exercise appetite-stimulating hormones. When equal amounts of exercise duration were compared for aerobic vs. resistance exercise, despite aerobic exercise burning more calories during the session, it was found that resistance exercise resulted in lower levels of the appetite-stimulating hormone ghrelin and higher insulin levels. Both are beneficial for reducing appetite following exercise.(11)
IS EXERCISE AN APPETITE SUPPRESSANT KEY POINTS
· Higher intensity exercise is associated with greater appetite suppression.
· Lactate levels produced during exercise can suppress the hunger-stimulating hormone ghrelin.
REFERENCES
1. Westerterp KR. Pattern and intensity of physical activity. Nature. 2001;410(6828):539-.
REFERENCES
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