What Can a Sudden Change in Diet & Exercise Do?

There are many reasons why you would suddenly change your diet or exercise routine. Maybe your work hours have changed and you have more time available. Or maybe you have a specific goal in mind, such as losing weight, and are making immediate changes to achieve that goal. Whatever the reason, a sudden change will cause your body to react accordingly.

If you're used to only exercising for a few minutes a couple of times a week, a sudden change can leave you feeling tired. Intense exercise can take a toll on your muscles and your cardiovascular system, leaving you sore and longing for more hours in bed. This should only last for a few workouts, however, until your body gets used to the change in routine. In the long run, exercise actually improves fatigue. According to a 2008 study by the University of Georgia, people who exercise for as little as 20 minutes three times a week will see an improvement in their energy levels. If you're also cutting down on your calorie intake while increasing your physical activity, your body might not have enough energy to keep you going. Make sure you don't crash diet, especially if you're exercising every day.

A sudden increase in the amount or the intensity of your workouts can cause a number of side effects. Extreme exercising can lead to dizziness, headaches, dehydration and low blood pressure. Over long periods of time, you might lose enough body fat that you disrupt your body's natural processes, including your monthly period if you're a woman. You also run the risk of injuring your knees or losing body mass, especially if the increase in exercise is accompanied by a significant change in eating habits as well.

Both food and exercise can have an impact on your mood. The impact could be positive or negative, depending on what drastic changes you're introducing. If you're sedentary and eat junk food on a regular basis, a sudden change can cause both good and bad side effects. On one hand, you might feel more relaxed and energized, as exercise can improve mood and help you fight stress, according to the National Children's Bureau. Drastically cutting calorie or carbohydrate intake, however, can leave you feeling moody and on edge, which is why it is best not to crash diet.

A sudden change in exercise and eating habits can help you break out of a weight loss plateau. According to certified personal trainer Davey Wavey, changing the intensity or the length of your workout can restart your weight loss. The same might happen if you switch to a different activity or try a radical change in diet, such as cutting down on fat, carbs or calories.