You need fuel to train, so fasting all day is not an option. If the day before you had dinner at seven o’clock in the evening, then in the morning you can easily go to the gym or go for a run, and at 11.00 have a hearty breakfast.
1. Your appetite may decrease.
You might expect to be hungry as hell after a period of calorie restriction, but this is often not the case because intermittent fasting affects the hormones that regulate appetite.
At first, when you just start practicing this method, the production of the “hunger hormone” ghrelin increases. But over time, when calorie restriction occurs regularly, the body adjusts and ghrelin levels decrease.
It also increases sensitivity to the “satiety hormone” leptin, so you feel fuller longer, which helps control weight.
2. On fast days you need to eat the right calories.
If you’re following the 5:2 routine, you may be confused about what to cook within your daily 500-600 calorie limit. It’s important to understand that not all calories are created equal—getting your energy from sources like fast-digesting carbohydrates, such as white bread or sweets, will cause your blood glucose levels to spike and only make you feel more hungry.
Instead, your meals on fast days, as well as on “normal” days, should contain protein, healthy fats and plenty of fiber to help you feel fuller longer. This way, you can be sure you’re getting the micronutrients you need to stay healthy.
3. You may have hunger rages.
When a person is hungry, his character deteriorates, he becomes gloomy and irritable. This is due to a drop in blood sugar levels. Additionally, prolonged fasting causes increased levels of the stress hormone cortisol, which can lead to increased anxiety in some people. The good news is that over time, the body will adapt and these side effects of fasting will go away.
4. You won’t be able to train at your usual pace.
On fasting days, your energy levels will drop, so you will have to adjust your pace of physical activity to the changed conditions. Start with low-intensity exercises and slowly increase the pace to the point where you feel discomfort.
Don’t force yourself to do what you did before – if you feel dizzy, nauseous or weak, stop training immediately.
5. You will have to drink more water than usual.
Some of the fluid enters the body with food, so on fasting days you will have to compensate for this deficiency and drink more than on “normal” days. It is especially important to remember this if you are exercising and sweat a lot.
6. Cardio at the beginning of the fasting period and strength training at the end
After strength training, it is important to build muscle mass, so it makes sense to time your workout towards the end of your fasting window. So, if you’re on a 16:8 diet and eat between 8 a.m. and 4 p.m., finish your strength training before breakfast, which should be high in protein.
But cardio training should be done immediately after the food “window” closes. That is, if you have dinner at 16.00, immediately after that you can go swimming, running, or cycling. In this case, dinner should be rich in carbohydrates, which will fuel your workout.