Here are a few of the most common side effects that I come across when people first start keto. Frequently the issues relate to dehydration or lack of micronutrients (vitamins) in the body. Make sure that you’re drinking enough water (close to a gallon a day) and eating foods with good sources of micronutrients. To read more on micronutrients, click here >
A well-balanced keto diet includes enough fat so that you are not hungry after a meal, can go for several hours without eating, and have ample energy. Make sure to increase your intake of fat at the start of your keto journey until your body adapts to using fat and ketones for most of its energy needs. Once you’re fat adapted, let your appetite guide you in cutting back on fat a bit until you reach the point where you can easily maintain the balance between hunger and satiety.
Additionally, you may find it difficult to eat adequate calories on a daily basis because fat is so filling. Some people even opt to fast for several hours each day. While this may help with weight loss, your body needs those calories for proper maintenance. Without them, it may turn to burning muscle for energy, and that can accelerate muscle loss.
Keto flu symptoms and side effects can include feeling tired, having difficulty sleeping, digestive issues like constipation, weakness during workouts, being moody, losing libido and having bad breath. Fortunately, these side effects don’t affect everyone and often only last for 1–2 weeks. (And yes, you CAN build muscle on keto.) Overall, symptoms go away as your body adjusts to being in ketosis.
A great long-term benefit of the ketogenic diet is reduced cravings for sugar and other unhealthy foods. However, you might initially have stronger cravings for carbs during the transition period. This can last anywhere from one to two days to around three weeks. But stick it out! At the end, you’ll be pleased with the reduced, and often eliminated, cravings.
At the core of the classic keto diet is severely restricting intake of all or most foods with sugar and starch (carbohydrates). These foods are broken down into sugar (insulin and glucose) in our blood once we eat them, and if these levels become too high, extra calories are much more easily stored as body fat and results in unwanted weight gain. However, when glucose levels are cut off due to low-carb intake, the body starts to burn fat instead and produces ketones that can be measured in the blood (using urine strips, for example).