If you were an exerciser before the diet you may notice some changes at the beginning of the Very Low Calorie Diet (VLCD).

During the first week on the diet you may not be able to perform at the same intensity you could prior to the diet. This is normal because your body is burning through its remaining carbohydrate and hasn’t yet adapted to using your body fat in the form of ketones for energy. It will take two to three weeks to fully adjust. During this time you may feel dragged out when exercising. It will pass.

When your ketone level stabilizes, around the fourth week of weight loss, your adaptation should be noticeable. However, some exercises such as resistance training, or anaerobic exercise, may be more difficult due to a decrease in total caloric intake.

If you haven’t exercised in the past, start slowly with a low-intensity program such as walking 30 minutes per day. Increase your intensity and duration as your fitness level improves and your weight drops.

After four weeks of weight loss, please schedule an Exercise Consult with one of our exercise physiologists. The exercise physiologist will help you develop an exercise program appropriate for your needs and fitness level.



  1. Drink plenty of water throughout the day. Be sure to drink water before, during and after exercise especially when it’s hot or exercise is prolonged or intense.
  1. Take at least one bouillon (up to three) 1 – 2 hours before exercise unless otherwise prescribed by The Hernried Center physician. Nutritional ketosis causes your body to lose sodium so you must continually replenish salt for optimum health.
  1. Stick with the program. It takes very little carbohydrate to reverse your body’s adaptation to ketones. Once this happens, it could be another month until your body re-adjusts and you are again symptom-free.
  1. Respect your body. Observe how well a nourished body can perform and take responsibility for your choices. The sense of well-being and vitality you will feel in a lean, nourished and exercised body is worth the effort.