Why The Keto Diet Makes You So Tired

If you recently started a keto diet, you may be noticing that you're constantly feeling tired or out of sorts. There are a few reasons that the high-fat, low-carb approach to eating may be making you fatigued, and while some of the reasons are indicators that the keto diet may not be right for you, others are easy to correct.

You may not be eating enough. This is the simplest cause of tiredness on the keto diet: When you shift to eating primarily fat as fuel, you may find it difficult to actually eat enough calories throughout the day, which can lead to feelings of fatigue. This is especially common if you're using the keto diet in order to lose weight and you've been used to doing caloric restriction-based diets in the past (via Perfect Keto). 

Unfortunately, you may not be aware that you're not eating enough. Ketosis can also lead to a suppressed appetite, so you may find that you need to monitor your caloric intake in order to ensure that you're eating enough to fuel your body throughout the day (via Healthline). Try simply adding more calories throughout the day at meals or with extra snacks to see if you feel less sleepy.

You may also need more carbohydrates. While the keto diet is low-carb, it does still allow for a small amount of carbohydrates in your daily meal plan, so make sure that you're not strictly eating fat and skipping protein and carbohydrate altogether. Your body does need at least a small amount of carbohydrates to function optimally.

What if I just started the keto diet and I'm tired?

If you're new to the keto diet, you may be suffering from the "keto flu." As your body shifts to primarily using fat for fuel, you may experience feelings of exhaustion and even more flu-like symptoms like brain fog, headaches, and gastrointestinal issues. This should only last for a couple of weeks, and eventually, these feelings should subside and you should start to feel an increase in alertness and brain clarity. 

Also, your sleep may be impacted by your diet shift. You may notice that you have trouble falling asleep or staying asleep as your body shifts into ketosis, and this lack of sound sleep throughout the night may be causing you to struggle during the day with feelings of exhaustion (via Medical News Today).

Additionally, you may be mildly dehydrated. Because a high level of ketones in the body can lead to dehydration, which can cause you to feel tired and lethargic, it's important to make sure you're monitoring your water intake and sipping water throughout the day, and make sure you're getting enough magnesium, potassium, and sodium, critical electrolytes for avoiding muscle cramps brought on by dehydration.