How to Banish Afternoon Fatigue

Afternoon Fatigue

Story at-a-glance -

  • Afternoon fatigue is a common complaint. One of the most common causes is post-lunch hypoglycemia, which is related to your inability to effectively burn fat
  • By switching your body over from primarily burning carbs to primarily burning fats for fuel or becoming “fat adapted,” you virtually eliminate such drops in energy levels
  • Besides replacing carbs with healthful fats, intermittent fasting is one of the most effective ways to encourage your body to change from burning carbs to burning fat, thereby boosting your mental and physical stamina
  • Working out in the middle of the day can give you an energy boost lasting three to four hours. If you prefer exercising in the evenings, it's best to avoid working out two to three hours before bedtime to avoid sleep disruption
  • If you’re not sleeping well, it will be next to impossible to avoid lagging energy levels. According to recent research, maintaining a regular exercise program can help improve your sleep over time

By Dr. Mercola

Many people experience a slump in energy levels by the time the afternoon rolls around. A number of factors may contribute to this phenomenon. The most common cause is post-lunch hypoglycemia, which is related to your inability to burn fat.

Hence, addressing your diet is key if afternoon fatigue is something you contend with on a regular basis. Besides alterations in your diet, intermittent fasting is one of the most effective ways to switch your body from burning carbs to burning fat, thereby boosting your mental and physical stamina.

Other factors are related to when and how much you exercise. Poor sleep also plays a role, of course, and recent research highlights the interconnectedness between sleep and exercise.

Diet Is Key for Maintaining Your Energy Levels

There are two fuels your body can use, sugar and fat. The sad reality is that our ancestors were adapted to using fat as their primary fuel and over 99 percent of us are now adapted to using sugar or glucose as our number one fuel source.

Because most are primarily burning carbs as fuel, afternoon fatigue is typically related to post-lunch hypoglycemia. By switching your body from using carbs as its primary fuel to burning fats instead, or becoming "fat adapted," you virtually eliminate such drops in energy levels. Overall, being adapted to burning fat instead of carbs has a number of benefits, including:

Having plenty of accessible energy on hand, as you effectively burn stored fat for energy throughout the day — One way to tell if you're fat adapted or not is to take note of how you feel when you skip a meal. If you can skip meals without getting ravenous and cranky (or craving carbs), you're likely fat-adapted.

Improved insulin and leptin sensitivity and decreased risk of virtually every known chronic degenerative disease.

Effectively burn dietary fat for your energy, which leads to less dietary fat being stored in your adipose tissue—hence the weight loss benefits associated with fat adaptation.

Being able to rely more on fat for energy during exertion, sparing glycogen for when you really need it. This can improve athletic performance, and helps burn more body fat. As explained by Mark Sisson, author of The Primal Blueprint, if you can handle exercising without having to carb-load, you're probably fat-adapted. If you can work out effectively in a fasted state, you're definitely fat-adapted.

First, Replace Carbs with Healthful Fats

Keep in mind that when we're talking about harmful carbs, we're only referring to grains and sugars, NOT vegetable carbs. You need very little if any of the former, and plenty of the latter. In fact, when you cut out sugar and grains, you need to radically increase the amount of vegetables you eat since, by volume, the grains you need to trade out are denser than vegetables. You also need to dramatically increase healthful fats, which include:

Olives and olive oil (for cold dishes)

Coconuts, and coconut oil (for all types of cooking and baking)

Butter made from raw grass-fed organic milk

Raw nuts, such as almonds or pecans

Organic pastured egg yolks


Pasture-finished meats

Palm oil

Unheated organic nut oils

Avoid highly processed and genetically engineered omega-6 oils like corn, canola and soy as they will upset your omega 6/3 ratio. Trans fats should also be avoided, but contrary to popular advice, saturated fats are a key component of a healthy diet. A reasonable goal will be to have as much as 50-70 percent of daily calories from healthy fat, which will radically reduce your carbohydrate intake.

Fat is far more satiating than carbs, so if you have cut down on carbs and still feel ravenous, it's a sign that you have not replaced them with sufficient amounts of healthy fat. Most people will likely notice massive improvement in their health and overall energy levels by following this approach. To help you get started on the right track, review my Nutritional Plan, which guides you through these dietary changes one step at a time.

How Intermittent Fasting Can Help

Once you've addressed your diet, you can try intermittent fasting. This will effectively help shift your body from carb- to fat-burning mode. Please do not embark on a fasting regimen if you're still subsisting primarily on processed foods and fast food meals, however. Since it involves skipping meals, making sure you're getting high quality nutrients with each meal you do eat becomes all the more critical.

Intermittent fasting involves timing your meals to allow for regular periods of fasting. It takes about six to eight hours for your body to metabolize your glycogen stores and after that you start to shift to burning fat. If you keep replenishing your glycogen by eating every eight hours (or sooner), you make it far more difficult for your body to use your fat stores as fuel.

Remember, your ancient ancestors never had access to a 24/7 supply of food like virtually all of us do with modern supermarkets. By necessity they regularly engaged in periods of fasting as they had no choice.

While there are several different intermittent fasting regimens, one of the easiest to implement simply involves restricting your daily eating to a narrower window of time, say 6-8 hours, instead of grazing all day long. This equates to 16-18 hours' worth of fasting each and every day—enough to get your body to shift into fat-burning mode. Once you have made the shift to burning fat as your primary fuel, you will be shocked at how your craving