Keto, Paleo, and Intermittent Fasting: Are they healthy for everyone?

It feels like a new diet trend pops up almost every week. You’ve probably heard friends talk about going keto, paleo, or trying intermittent fasting—and maybe you’ve wondered if any of them actually work. The truth is, these diets all have their pros and cons. Let’s take a closer look at what each one really means and how they might (or might not) fit into a healthy lifestyle.

The Keto Diet

The keto diet is all about cutting way back on carbs and eating more fat. The idea is to push your body into a state called ketosis. That’s when your body runs on fat for energy instead of sugar from carbs. Some keto diets recommend no more than 50 grams of carbohydrates per day, which is about the amount of carbs you’ll find in a bagel.

People who follow keto usually skip bread, pasta, and sweets, and eat more foods like eggs, meat, avocado, cheese, nuts, and oils. Some people lose weight on keto or notice steadier energy. Other benefits include reduced blood sugar, decreased blood pressure, and decreased triglycerides (fats that are usually measured alongside your cholesterol).

The keto diet can be tough to keep up long term. Here are some of the issues that might pop up when following a keto diet:

• The keto “flu”: When you eliminate carbohydrates from your diet suddenly, your body can react with flu-like symptoms that can last up to a week after starting the diet.
• Kidney stones: Diets with high protein and low in carbohydrates may increase the risk of kidney stones.
• Nutritional deficiencies: When strictly following the keto diet, you cut out food groups (like fruits, whole grains, dairy, and starches) that help to provide your body with essential nutrients like potassium, sodium, and magnesium.
• Not enough fiber: Whole grain carbohydrates are filled with fiber so eliminating them from your diet makes it very difficult to get a sufficient amount of fiber.

The Paleo Diet

The paleo diet is built around how humans supposedly ate thousands of years ago—think lean meats, fish, fruits, veggies, nuts, and seeds. It skips processed foods, grains, beans, and dairy. The goal is to eat fewer additives and more whole foods. Benefits include reduced body weight and weight circumference, lower blood pressure, and lower cholesterol.

Paleo can help you focus on nutrient-rich foods, but it’s also restrictive. Here are some concerns with the Paleo diet:

• Micronutrient deficiencies: Paleo diets result in a reduced intake of thiamine, folate, magnesium, calcium, iron, and iodine.
• Lack of fiber: Fiber is thought to reduce the risk of developing heart disease, irritable bowel system (IBS), colon cancer, and diabetes.
• Increased saturated fat: The American Heart Association notes this diet doesn’t line up with their cardiovascular health guidance, as the diet restricts whole grains and legumes (foods consistently associated with reduced morbidity and mortality), while potentially increasing saturated fat from animal sources.

Intermittent Fasting

Intermittent fasting isn’t about what you eat—it’s about when you eat. Many people follow simple patterns like 16:8 (fast for 16 hours, eat during an 8-hour window). Some find it helps them lose weight, and it can result in reduced blood pressure and cholesterol. Fasting can work for certain people, especially if it helps them avoid constant snacking or late-night munching. But it’s not for everyone—those with diabetes, who are pregnant, or who have a history of disordered eating should avoid it unless advised by a doctor. Additional concerns include:

• Nutrition concerns: Risk of dehydration, low blood pressure, and fainting are possibilities if nutritional needs aren’t met.
• Side effects: Some people experience symptoms during the fasting stage such as irritability, headache, stomach upset, dizziness, and difficulty concentrating. These symptoms are more pronounced in the first month.
• Potential increased mortality: One study found that keeping your eating window really short (8 hours or less) was linked to a 30%+ higher risk of dying from any cause and over a 50% higher risk of heart-related death—especially among older adults, men, and White individuals.

So, Which Diet Is Best?

The truth is, there’s no single “best” diet for everyone. What matters most is finding a way of eating that helps you feel good, gives you energy, and is realistic to stick with.
Whichever plan you choose, focus on:

• Eating mostly whole, unprocessed foods
• Getting a mix of carbs, protein, and healthy fats
• Incorporating fresh fruits and vegetables into your diet
• Staying hydrated
• Listening to your body

And if you’re thinking about making a big change to your diet, it’s always smart to talk with your healthcare provider first. They can help you create a balanced plan that fits your lifestyle and health goals.