I Tried the Paleo Diet for 21 Days — Here’s What Happened

Diets come in all shapes and sizes. Some are based on science and are balanced, sustainable, and healthy. Others are nothing more than fads that involve following nonsensical eating plans seemingly based on the whims of the author. They ban or promote certain foods for no logical reason.

I’m a veteran personal trainer and nutrition coach and I’ve spent the last three-plus decades studying and testing various diets – from the safe and effective to the ridiculous and pointless. I then use my experiences to help clients achieve their health and fitness goals.

Of all the diets I’ve studied, the Paleo diet is one that’s always fascinated me. Maybe I was a hunter-gatherer in a previous life but eating only foods you can catch, kill, or forage appeals to my inner caveman.

But, while I like the idea of the Paleo diet, I have never actually tried it. That all changed when I was challenged to follow this controversial eating plan for three weeks.

In this article, I share my experiences and results from following the Paleo diet for three weeks.

What is The Paleo Diet?

The Paleo diet, short for Paleolithic diet, is an eating plan based on how people ate back during the Paleolithic (Old Stone Age) era, which began around 2.5 million years ago and ended approximately 12,000 years ago (1).

During this time humans were hunter-gatherers and did little if any subsistence farming. Instead, our paleo ancestors mostly ate wild game, fish, plants, nuts, seeds, and other foods they could find on foraging trips.

They had limited access to grains, dairy, and other Neolithic (New Stone Age) foods, which became more common when humans began living in settlements and farming for food.

Some experts believe that many of the illnesses that affect modern humans, such as type 2 diabetes, obesity, and heart disease, didn’t exist in Paleolithic times and only started to emerge with the shift from hunting-gathering to farming. Consequently, the so-called oldest diet plan is often promoted as being very healthy.

While this is a controversial point of view, it’s certainly true that many modern diseases are directly attributable to food (2), and the modern refined, sugar-laden diet is very different from what people ate 12,000 years ago.

Foods not allowed on the Paleo include:  

1. Grains – including wheat, rice, oats, barley, and corn.
2. Legumes – such as beans, lentils, chickpeas, peanuts, and soy products.
3. Dairy – milk, cheese, yogurt, and other dairy-based products.
4. Processed foods – anything refined, packaged, or artificially enhanced.
5. Refined sugar – table sugar, high-fructose corn syrup, and artificial sweeteners.
6. Vegetable and seed oils – including soybean, canola, sunflower, and corn oils.
7. Processed meats – such as deli meats, sausages, and hot dogs with additives.
8. Artificial additives – preservatives, flavor enhancers, and colorings.
9. Soft drinks and sweetened beverages – including soda, fruit juices, and energy drinks.
10. Alcohol – most forms of alcohol, as fermentation-based drinks were not part of early human diets.
11. Fast food – due to the reliance on refined ingredients and unhealthy fats.
12. Trans fats and hydrogenated oil – commonly found in margarine and processed snacks.
13. Refined flour – including white flour and anything made from it, such as bread and pasta.
14. Artificial sweeteners – including aspartame, sucralose, and saccharin.
15. Packaged snacks – chips, crackers, cookies, and anything with refined ingredients.

Related: The Ultimate Paleo Diet Food List: What to Devour & Resist

Instead, paleo-approved foods include anything you could hunt, pick, or forage in nature. So, if a food has been in any way manufactured or processed, it is not paleo. For example, contrary to what you might have hoped, donuts and hotdogs do NOT grow on trees!

My 21-Day Paleo Diet Meal Plan

Having never followed the paleo diet before, I spent some time researching this eating plan and creating a simple seven-day menu that I could repeat three times to make 21 days.

This pre-planning helped make the transition from a modern diet to paleo as easy as possible. After all, knowing what you are going to eat from one day to the next limits your choices and makes grocery shopping and meal prep much easier.

7-Day Paleo Menu

Day 1 

• Breakfast: Scrambled eggs with spinach, mushrooms, and avocado.
• Snack: Handful of almonds and blueberries.
• Lunch: Grilled chicken salad with mixed greens, cherry tomatoes, cucumbers, olive oil, and lemon dressing.
• Snack: Apple slices with almond butter.
• Dinner: Baked salmon with roasted Brussels sprouts and mashed cauliflower.

Day 2 

• Breakfast: Banana pancakes (mashed banana, eggs, and cinnamon) with a side of strawberries.
• Snack: Carrot sticks with guacamole.
• Lunch: Grass-fed beef lettuce wraps with avocado and tomato.
• Snack: Handful of walnuts and a small handful of grapes.
• Dinner: Grilled shrimp with zucchini noodles and a garlic-lemon olive oil drizzle.

Day 3

• Breakfast: Chia pudding with coconut milk, cinnamon, and raspberries.
• Snack: Boiled egg with a few olives.
• Lunch: Turkey and avocado salad with mixed greens, bell peppers, and balsamic dressing.
• Snack: A handful of cashews and half an orange.
• Dinner: Roast chicken with roasted sweet potatoes and sautéed kale.

Day 4 

• Breakfast: Omelet with mushrooms, bell peppers, and onions, served with fresh berries.
• Snack: Coconut flakes and a handful of macadamia nuts.
• Lunch: Grilled steak with a side of arugula and cherry tomato salad.
• Snack: Sliced cucumber and celery with almond butter.
• Dinner: Pan-fried cod with steamed asparagus and mashed butternut squash.

Day 5

• Breakfast: Scrambled eggs with bacon and sautéed spinach.
• Snack: Handful of mixed nuts and a pear.
• Lunch: Grilled chicken with roasted beets, arugula, and walnuts.
• Snack: Hard-boiled egg with a few slices of cucumber.
• Dinner: Bison burger (no bun) with sautéed mushrooms, onions, and a side of roasted carrots.

Day 6 

• Breakfast: Coconut yogurt with sliced banana, flaxseeds, and cinnamon.
• Snack: Small handful of pecans and blackberries.
• Lunch: Tuna salad with avocado, cucumber, and leafy greens.
• Snack: Fresh pineapple slices with a few almonds.
• Dinner: Grilled lamb chops with roasted cauliflower and a side of sautéed greens.

Day 7 

• Breakfast: Scrambled eggs with smoked salmon and avocado.
• Snack: A few strawberries and walnuts.
• Lunch: Grilled chicken with roasted broccoli, cherry tomatoes, and lemon dressing.
• Snack: Apple slices with coconut butter.
• Dinner: Baked trout with roasted asparagus and garlic mashed sweet potatoes.

Week One – Learning to Hunt and Gather at The Grocery Store

Grocery shopping as a newbie hunter-gatherer was an interesting experience. It’s only when you cannot eat processed foods that you realize how much of the modern diet isn’t paleo.

Even armed with my shopping list, I had to think carefully about everything I bought, often asking myself, “If I was a caveman, would I be able to find this food in nature.”

If I couldn’t imagine catching, killing, or picking it, the food stayed on the shelf.

I found that sticking to the vegetable and fruit aisles and the meat and fish counters eliminated most processed foods from my shopping cart, although it did take a lot of willpower not to pick up bread, rice, pasta, and the rest of my usual diet staples.

Eating-wise, I found paleo meals tasty and easy to prepare. They were also filling, and despite not eating a lot of carbs, they still provided me with adequate energy.

Week Two – Difficulties Dining Out

By week two, I was feeling confident enough to try swapping a homemade meal with going out for dinner. This turned out to be a mistake because very few restaurants cater to wannabe cavemen!

In the end, I had to order a steak and vegetables and ignore the complimentary fries and breadbasket, and dessert was limited to some fruit. All in all, it was a very disappointing dining experience, which helped illustrate just how restrictive the paleo diet can be.

This issue aside, I continued to enjoy Paleo-style cooking and eating but did notice that all the meat and fish were making my weekly grocery shopping trip more expensive. I guess cavemen earn more than personal trainers/fitness writers…!

Partway through week two, I started to experience some issues with cravings. I wasn’t hungry, but I was missing things like bread, cereal, rice, and pasta. I especially missed my morning maple syrup-drenched oatmeal, which is probably my favorite meal of the day.

Still, I put my cravings aside and stuck to my menu. After all, I was starting to see and feel the benefits of this diet and didn’t want to hurt my results.

Week Three – Learning to Love Meat and Veggies

While the paleo diet can be as varied as you want it to be, when you get down to its core, you’re mostly eating meat and plants. Sure, the “meat” could also be chicken, fish, or eggs, but it’s still variations on the meat theme. Add some vegetables or fruit and you’ve got yourself a paleo dinner, or breakfast, or lunch!

Consequently, from a taste and texture point of view, the paleo diet can feel a little repetitive as the meals are often very similar. This could be a drawback if you prefer a more varied menu, and it goes without saying that this is not a diet for vegetarians or vegans.

Of course, meat and plants provide many of the nutrients your body needs, especially protein, vitamins, minerals, and fiber. It’s the abundance of these things and the lack of sugar, salt, trans fats, etc. that makes the paleo diet potentially healthier than the average modern diet.

As an added benefit, paleo meals are often very easy to prepare, and most of mine involved grilling. After all, what’s more caveman than tossing some meat and veggies on a flaming grill?

Results of Following the Paleo Diet for Three Weeks

I followed the paleo consistently for three weeks and didn’t cheat at any point. This ensured that my one 21-day experiment provided the best possible results:

More Stable Energy

Most paleo foods have a low to moderate glycemic index score. This means they digest relatively slowly and don’t cause big spikes in blood glucose. Consequently, my energy levels felt very stable while following the cavemen diet, with none of the highs and lows I normally experience during the day.

Unplanned Fat Loss

I didn’t count calories or macros during my three-week paleo experiment. Instead, I just ate fairly large portions so that I never felt hungry or deprived. Despite this, I still lost fat during my paleo diet and was visibly leaner by the end. This was probably because of the increased protein intake and not consuming any refined grains or sugar.

Improved Digestion

Many foods allowed on the paleo diet are high in fiber. In contrast, modern processed foods have most of their fiber removed. Eating more dietary fiber had a noticeable effect on my digestive system and, at the risk of oversharing, made my bowel movements easier and more regular. I also experienced no bloating, stomach upsets, etc. during this diet.  

Increased Muscle Mass and Strength

The paleo diet is naturally high in protein. Eating meat, fish, eggs, poultry, etc., at most main meals meant I got more of this muscle-building nutrient than normal, and without having to resort to using protein powder. Eating more protein helped me add a little extra muscle mass which, in turn, increased my strength.

Improved Sleep

I slept very well during my three-week paleo experiment. I fell asleep more quickly and woke up less often during the night. This, I suspect, was because most modern processed foods wreak havoc on your blood glucose. Blood glucose fluctuations can interfere with your circadian rhythm, disrupting your sleep cycle.

Closing Thoughts

While I recognize that the paleo diet is not suitable for everyone, it’s a great way to eliminate refined and processed foods from your diet and eat more naturally. However, giving up things like bread, rice, pasta, dairy, etc., is not easy, and may not even be necessary because, in moderate quantities, these foods can still be healthy.

That said, even if going full paleo doesn’t appeal to you, replacing a few processed meals a week with caveman-approved foods will undoubtedly do you good.

Have you tried the paleo diet? How did it go? Share your experience and thoughts below – I’d love to hear from you!

References:

1. Singh A, Singh D. The Paleolithic Diet. Cureus. 2023 Jan 25;15(1):e34214. doi: 10.7759/cureus.34214. PMID: 36843707; PMCID: PMC9957574.
2. Bidlack WR. Interrelationships of food, nutrition, diet, and health: the National Association of State Universities and Land Grant Colleges White Paper. J Am Coll Nutr. 1996 Oct;15(5):422-33. doi: 10.1080/07315724.1996.10718620. PMID: 8892167.

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