A common assumption about exercise is that it will motivate you to eat more. But recent research turns this assumption on its head by showing that 45 minutes of moderate-to-vigorous exercise in the morning may actually reduce your food cravings. The study included 18 women of normal-weight, and 17 who were clinically obese. Their neural activity in response to images of food was measured on a morning following exercise, and on a morning when they did not exercise.
Images of flowers were used as a control. Perhaps surprisingly, they discovered that the women's attentional responses to images of food decreased after a brisk walk on the treadmill.
According to co-author James LeCheminant:
"This study provides evidence that exercise not only affects energy output, but it also may affect how people respond to food cues... We wanted to see if obesity influenced food motivation, but it didn't. However, it was clear that the exercise bout was playing a role in their neural responses to the pictures of food."
In both groups of women, morning exercise also resulted in an increase in total physical activity that day, and, perhaps more importantly, they did not compensate for the energy expenditure by eating more later in the day.
Exercising first thing in the morning, especially if done on an empty stomach, has been shown to be particularly beneficial. Your choice of breakfast food may also play a significant role in decreasing or heightening sensations of hunger afterward.
Why Eating Breakfast Might Increase Hunger
The interesting aspect about eating first thing in the morning is that it coincides with your circadian cortisol peak, that is, the time of day when your cortisol (stress hormone) levels rise and reach their peak. The circadian cortisol peak impacts your insulin secretion in such a way that when you eat during this time, it
leads to a large and rapid insulin release and a corresponding rapid drop in blood sugar levels, more so than when you eat at other times of the day.
If you're healthy, your blood sugar levels won't drop to a dangerously low level (such as what can occur with hypoglycemia) but they can drop low enough to make you feel hungry. This is more commonly experienced in people who are not insulin resistant (such as those who are overweight or have type 2 diabetes), but rather are lean and "insulin sensitive." Because the circadian cortisol peak adds another insulin-boosting effect on top of an already insulin-sensitive individual, the low blood sugar and subsequent hunger may therefore be more pronounced.
It's also important to realize that eating a full meal, particularly carbohydrates, will inhibit the sympathetic nervous system (SNS) and reduce the fat burning effect of your exercise. Instead, eating lots of carbs activates your parasympathetic nervous system (PSNS), which promotes energy storage – the complete opposite of what you're aiming for.
Although conventional wisdom states breakfast is the most important meal of the day, skipping breakfast may actually help you control your appetite throughout the day. Skipping breakfast is also an easy way to implement intermittent fasting, which has a number of well-documented health benefits, including weight loss and improved weight management as you become increasingly fat-adapted.
Keep in mind that it takes about six to eight hours for your body to metabolize your glycogen stores and it's only after that that you actually start to shift to primarily burning fat as fuel. If you keep replenishing your glycogen by eating every eight hours, you make it far more difficult for your body to actually shift to fat burning mode, so when using intermittent fasting, make sure your fasting period is long enough (12-18 hours). You will need to start gradually though and take a few weeks or more to get to 12 hours and eventually longer.
eliminate breakfast and restrict the time You eat to a period of about six to seven hours, typically from noon to 6 or 7 pm. Our ancestors rarely had access to food 24/7 like we do today, and it makes sense that our genes are optimized for intermittent fasting. Take Protein about 30 minutes after the workout to provide nutrients, especially leucine, for muscle growth and repair.
A growing body of intriguing research indicates that intermittent fasting may be a key weight loss tool – especially when combined with exercise in a fasted state . so why not give it a try ?
But remember ,
When exercising in a fasted state, it’s critical to eat a recovery meal within 30 minutes post-workout. This meal should NOT be skipped in the name of fasting. Fast-assimilating protein, such as whey, is ideal for brain and muscle recovery...
