Have you ever wondered why you feel hungry on rest days? For some people, feeling hungry after exercise is one of the number one reasons why they don’t lose weight.
Exercise and hunger seem to go different ways for different people. Some people get hungrier, whereas others feel like they cannot eat. Either way, I went in search for the explanation as to why, after a long week of training, I feel hungrier on the weekend (when I don’t train).
One thing to note: there is no one reason to explain why people get hungry on rest days, but several possible explanations that may or may not be true for everyone. Keep in mind that everyone’s slightly different; nutrition doesn’t have a ‘one size fits all’ approach.
7 reasons why you may feel hungry on rest days
Hunger increases to support muscle recovery
One of the main reasons why anyone trains is to achieve the adaptations to training. Training increases muscle mass, which increases metabolism. This may help you increase in muscle size or skill. With vigorous aerobic training, working muscles burn calories to achieve weight loss. Even if you don’t have a body composition goal, and you exercise for fun or enjoy technical sports, you’re still breaking down muscle, which increases lean muscle mass in the areas that you are using.
Whenever you break down muscle, it takes a significant amount of energy to repair those tissues. Amino acid proteins are broken down from food and used to rebuild muscle. This means after exercise, especially if it’s hard exercise, you will have increased energy needs. It is plausible that you feel hungry on rest days because your body is recovering from previous training sessions.
Post exercise appetite suppression
Hunger levels may “feel” elevated because on training days you experience post-exercise appetite suppression. As mentioned earlier, there are two categories that exercisers usually fall in to; those that get hungrier after exercise and those who feel like they can’t eat after exercise.
For exercisers who lose their appetite after training, they may find that because of this, especially if they are training twice a day, they may not feel hungry on training days. This makes rest days feel like their hunger levels have gone haywire.
More time spent training, less time spent eating
If you’re spending a significant amount of time at the gym training or outdoors running, you’re obviously not eating. This means for a significant amount of time you’re not around food or thinking about food, ultimately giving you less time in the day to notice you’re hungry. Obviously, some people would still feel hungry but not act on the hunger, or take a protein shake to the gym, whereas others may just ignore the hunger. Your environment plays a large role in what you choose to eat or not eat, and weather your appetite is stimulated. A lot of people salivate over the smell of hot chips prompting them to eat. The opposite is also true, if you’re in an environment not conducive to eating (the gym), then you will not eat. With less food around you will probably eat less.
Energy deficit compensation
There have been a number of studies that have shown in some groups of exercisers there is a significant amount of energy intake, and energy expenditure compensation going on post exercise.
Exercise obviously creates an energy deficit over a number of back-to-back training days. For some exercisers, they either don’t have the opportunity to replace these calories because they are A. too busy and forget (think office workers) or B. train too much and can’t get enough food in (think athletes).
This energy deficit is noticed by the body. One thing most people don’t know is that the human body doesn’t like to lose weight. It likes things to be consistent, so this pending energy deficit is fixed on rest days. The body increases levels of hunger hormones, like ghrelin, to entice you to eat more to replace energy lost during the week.
Simultaneously, it has also been documented that other sedentary compensatory behaviours occur after exercise, to prevent further losses in energy. Not only do people eat more, they also sit more, walk less and choose higher carbohydrate foods. 
In one particular study, they monitored groups of men and women who completed a weight loss exercise program over a 10month period. The goal was to monitor what these people did after exercise. The men who exercised lost weight, however the female group didn’t. This was because the female group would eat more after exercise and on rest days with an increased intake between 121- 285kcal daily for those expending between 400-600kcal during exercise.
There are two things going on with these people in the study: metabolic and behavioural compensatory responses. Metabolic compensatory responses include changes in gut peptide levels increasing appetite or reduced metabolic rate because of too much exercise or lack of food. Behavioral responses are resting and eating more. The research paper explains this more in depth. As you can imagine metabolic responses can influence behavioral responses, so one can heighten or increase the impact of the other. No wonder you feel hungry on rest days!
I am actually the type of person who will eat more when I ramp up my training. For example, when I was training for my long course triathlon event I would get so hungry towards the end of the week. By Thursday, I would have completed 9km of swimming, 18km of running, and 60-70km on the bike. Nothing would satisfy my hunger. I knew I was eating more than what I had burnt off, but the hunger was insatiable, so I kept eating. My solution after the race was to train less and it fixed my issue. I also know that if I don’t sleep enough I feel hungrier and I typically stay up late on the weekends (my rest days) and so that also impacted what and how much I ate.
I know that if I do more than 2hours of exercise a day, my eating goes through the roof. The outlay of time in exercising is not worth the time spent, if I am negating performance gains with weight gain.
Reduced snacking on rest days
For the readers on a devised meal plan from a sports dietitian or myself, you might notice that you have less to eat on rest days. Typically, pre and post training snacks are only eaten pre and post training, therefore if you don’t train you should be eating less. The body does get used to a certain amount of food coming in every day, especially if you’re regimented with your meal times. You might feel hungry on rest days because those extra snacks aren’t coming in when they usually do.
Drinking less on rest days
On exercise days you probably drink a lot more water than you do on rest days. This is because exercise can make you feel like you have a dry mouth and you may be extra conscious about hydration. However, on rest days this may not be the case. A lot of people mistake thirst for hunger and eat, rather than drink. It’s possible that you think you feel hungrier on rest days, when in fact you just feel thirsty.
Lower levels of circulating catecholamines
Catecholamines is a big word, but don’t worry they aren’t that scary and necessary for exercise. Catecholamines is a group name for hormones made by the adrenal glands, namely adrenaline, noradrenaline and dopamine. These are also hormones used in the fight or flight response. During high intensity exercise, these circulating hormone levels increase to maintain a constant blood sugar level so you can continue exercising. Namely, they up-regulate the release of glucose from the liver.
When you stop exercising the hormone levels also drop over time, and blood sugars drop with it. When blood sugar levels drop, you feel hungry. In addition, the body now detects that glycogen (glucose) stores in the liver and muscles have also been depleted from the exercise itself. The brain now ramps up the feelings of hunger to begin the refuelling process.
The human body is a weird and wonderful machine to say the least!
- Resistance to exercise-induced weight loss: compensatory behavioural adaptations. E.Melanson et al. Journal of Medicine, science sports and exercise pg 1600-1609, 2013
- Hopkins et al. The Relationship between Substrate Metabolism, Exercise and Appetite Control Does Glycogen Availability Influence the Motivation to Eat, Energy Intake or Food Choice? Sports Med. 2011 Jun 1;41(6):507-21.