The paleo diet resembles the way of eating of human ancestors during the Paleolithic era. It can be noted that prehistoric people mostly consumed protein sources like seafood, game animals, and plants like fruits, nuts, and seeds.

With a different food supply now, the modern-day paleo diet involves eating whole, minimally processed foods. These include lean meats, fish, vegetables, and fruits.

The diet also discourages eating dairy, grains, legumes, and most types of added sugar.

A well-rounded paleo diet can provide several health benefits, such as weight loss. However, when followed the wrong way, it could also cause several side effects. So how does the paleo diet affect your body?

Here are 5 adverse effects of a paleo diet.

1. Bad Breath

The Paleo diet may cause bad breath. This may be caused by low carb intake, allowing your body to reach ketosis. Ketones can be unpleasant, but their effects on the breath can differ from person to person.

In addition, increased protein intake can cause the gut to produce hydrogen sulfide as part of digestion, which can lead to what we call sulfur burps. This burp can have an eggy smell.

2. Constipation

The Paleo diet is not necessarily considered a low-carb diet. Although it cuts out common carb sources like grains and added sugar, it encourages eating fiber-rich foods like fruits, vegetables, nuts, and seeds.

However, if you don’t eat enough fiber from these paleo-friendly fiber sources, you could experience constipation.

For example, transitioning from a high-carb, plant-based diet to a low-carb paleo-like diet will significantly reduce your fiber intake.  This can disrupt the digestive system.

It should be noted that fiber helps speed up the transit of food in the digestive tract, thus preventing constipation.

Constipation can be painful and negatively affect your health. So make sure to eat plenty of fruits, vegetables, and other protein food sources when following the paleo diet.

3. Diarrhea

Many people don’t get enough fiber every day.

The recommended daily fiber intake for men under 50 is 38 grams and 25 grams for women of the same age.  Unfortunately, the majority of the people in the United States eat only about 15 grams of fiber daily.  This is probably because most modern-day diets are low in fiber-rich foods and high in ultra-processed foods.

The paleo diet is rich in fiber, and switching from a low-fiber diet to a paleo diet could result in diarrhea due to the laxative effect of fiber.

In addition, eating a high-fat diet like a paleo diet may also cause diarrhea for some people, especially those with irritable bowel syndrome (IBS).

In fact, eating a paleo diet has been found in one study in 39 healthy women to significantly increase participants’ risk of having diarrhea.

4. Changes in gut bacteria

Following a paleo diet long-term has also been suggested in a recent study to cause changes in gut bacteria.

For example, people following the paleo diet have been shown in one study to have lower levels of certain beneficial bacteria and higher levels of harmful Hungatella bacteria—certain gut bacteria that produce a compound called trimethylamine (TMA), which can then be turned into trimethylamine N-oxide (TMAO).

TMAO has an atherogenic effect, which may result in an increased risk of certain conditions, such as kidney and heart disease.

Also, people on a strict paleo diet have lower consumption of resistant starch—a type of carbohydrate that feeds beneficial gut bacteria.

Therefore, following a diet that eliminates legumes and grains long-term may not be beneficial for gut health.  Further research is however necessary to fully elucidate the diet’s effects on gut health.

5. Fatigue

A too restrictive diet can result in low energy levels and feelings of tiredness because it does not provide sufficient nutrients, such as carbs, and calories.

Low-carb diets like the keto diet have been found to cause fatigue due to depleted glycogen stores.

Stored in your liver and muscles, glycogen is a form of energy that is used as a quick fuel source for the body.

Bear in mind that in the paleo diet, you can increase your carb intake by eating more paleo-friendly carb sources like fruit, squash, and sweet potatoes. The diet is not necessarily considered a low-carb diet.

How to Minimize Them?

Although the paleo diet has been found in some studies to cause a few mild side effects, most studies observed that the adverse effects of the paleo diet are generally well-tolerated. When following a well-rounded paleo diet, you can prevent these effects.

Here are a few helpful tips for eating a well-rounded paleo diet.

1. Make sure to get enough fiber every day by eating fruits, vegetables, nuts, seeds, and other fiber-rich products.
2. Consider following a modified paleo diet, which is less restrictive.  It has been suggested in one study to be beneficial for gut health.
3. Eat balanced meals regularly and appropriately, i.e. make sure you eat meals according to your weight goals, activity levels, age, and body size.
4. Always remember that the paleo diet is not necessarily a low-carb diet; you can increase your intake of starchy vegetables and fruits if needed.
5. Before switching to a paleo diet, make sure to seek the advice of a registered dietitian as they can help you plan your meals and ensure that you get the nutrients your body needs, and help you feel your best.

Any dietary pattern could potentially cause nutrient deficiency. Restricting your intake of foods like grains and legumes could put you at risk of underconsuming certain nutrients. However, modified paleo diets have been shown in studies to cause minimal nutritional risk compared with the standard paleo diet.

If you are following a strict paleo diet, make sure to eat sardines, leafy greens, seeds, and nuts to get enough calcium.

The Takeaway

When followed correctly, the paleo diet can be a healthy eating pattern; however, it may also cause some mild adverse effects, especially when it is too restrictive.

It may result in food cravings, constipation, diarrhea, changes in gut bacteria, and fatigue in some people.

To minimize these adverse effects, consider following the modified paleo diet so you can get enough nutrition.