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The 21-Day Bone Broth Diet: Is It Keto?


The bone broth diet is a simple intermittent fasting regimen. It’s bone broth two days per week, and a paleo diet the other five days. 

The 21-day bone broth diet is said to help you lose weight. Although there’s no scientific evidence supporting this claim, intermittent fasting (as a general practice) has been shown to improve body composition and promote weight loss[*][*]. 

Drinking bone broth has other benefits too, unrelated to fasting. That’s because, when you consume more bone broth, you consume more collagen — and there’s a lot to like about collagen. 

Read on to learn about the 21-day bone broth diet, the benefits of bone broth, and the best sources of bone broth. And yes, you’ll even get a sample bone broth meal plan.

What is the 21-Day Bone Broth Diet?

The 21-day bone broth diet is a type of intermittent fasting (IF) program called 5:2. This ratio stands for five days of feeding and two days of fasting each week.

Generally speaking, intermittent fasting is the practice of taking regular breaks from food. These breaks can be implemented daily (a 16 hour daily fast), or at longer intervals (the 5:2 bone broth diet).  

Intermittent fasting, the research shows, may promote a slew of health benefits. More on this later, but back to broth for now. 

The 21-bone broth fast was popularized by Dr. Kellyann Petrucci — an author and naturopath — as a way to detox your body, lose weight, and heal your gut. While there isn’t peer-reviewed data behind these claims, there is some evidence that collagen is crucial for gut health and that intermittent fasting can stimulate weight loss[*][*].  

Okay, here’s how the bone broth diet works. Two days out of the week, you drink 3-6 cups bone broth, about 300-500 calories worth in total. 

And that’s it for your “fasting days”.

The other five days are your “feeding days”. On these days, you eat a paleo diet. 

When you eat paleo, you avoid grains, refined foods, sugar, alcohol, legumes, and (sometimes) dairy. A good rule of thumb is to shirk foods that come in a package. 

What can you eat on paleo? Plenty. Here’s a short list:

  • Meat like beef, chicken, pork, and lamb
  • Fish like salmon, tuna, sardines, and cod
  • Any fruits and vegetables (favor organic and locally grown produce)
  • Nuts like almonds, walnuts, cashews, and macadamia nuts (and nut butter!)
  • Healthy fats like olive oil, coconut oil, avocados, and unrefined palm oil 
  • Starchy tubers like yams, carrots, and potatoes
  • Bone broth, as much as you like

The paleo diet, in fact, is rather similar to a whole foods ketogenic diet. The main difference is that carbs from fruits and tubers are allowed on paleo, but not on keto. 

Benefits of the Bone Broth Diet

First of all, no clinical research exists on the bone broth diet. Because of this, the following benefits are a bit speculative. 

That said, there are three main ways the bone broth diet might improve your health:

  1. By eliminating unhealthy, processed foods when converting to a paleo or whole foods style of eating
  2. Through intermittent fasting
  3. By boosting your intake of collagen protein — the main protein in bone broth

Wait. Isn’t bone broth a good source of minerals? 

Depends how long you cook the bones. One study, for instance, showed that commercially made bone broths (cooked under eight hours) yielded negligible levels of calcium and magnesium. But cooking them for longer — in a lower PH — yielded higher levels of minerals[*].

The lesson here is to cook your bones for 20-36 hours, or buy your bone broth from a company that does.

So in terms of bone broth benefits, minerals are a maybe. 

Here’s the thing. Assuming you were eating healthy to begin with, most benefits from bone broth fasting come from intermittent fasting and collagen.   

Intermittent Fasting On the Bone Broth Diet

In the modern world, food is rarely scarce. If you want a snack, it’s not hard to find. 

It wasn’t like this for most of human history. Sixty thousand years ago, there wasn’t a store selling fresh meat and berries — and early hominids often went days without eating. 

Fortunately, the human body is marvelously adapted to fasting. When you stop putting energy (food) down your gullet, your cells start burning another fuel source: body fat. 

And when you burn fat, you produce ketones — little molecules that power your brain and send anti-inflammatory signals all throughout your body[*]. Ketones are a big reason you feel more alert on a fast.

Fasting also initiates a powerful “clean and recycle” program in your cells called autophagy. Autophagy allows your cells to digest old and unused parts — and replace them with new ones. 

This is desirable. Animal studies, in fact, link autophagy to longevity[*]. In humans, impaired autophagy is tied to a long list of diseases like Alzheimer’s, Parkinson’s, heart disease, and amyloidosis[*][*]. 

It’s hard to measure autophagy in humans, but as a general rule: longer fasts will induce more autophagy than shorter ones. 

Finally, intermittent fasting has been shown — in multiple studies — to help with both weight loss and fat loss[*][*].  

This may be a case of less calories in, less weight gained. But since IF also increases insulin sensitivity, there may be a deeper metabolic reason behind the weight loss[*]. 

To be clear, a bone broth intermittent fast hasn’t been tested in the lab. But similar IF setups have yielded positive results, so it’s certainly reasonable to draw the comparison[*].  

Collagen From Bone Broth

Bone broth is high in collagen, the most abundant protein in the human body. Collagen resides in your skin, hair, joints, and even organ tissue. 

According to the research, collagen supplementation has a variety of health benefits. Here are some of the main ones, along with brief descriptions:

  • Skin health: When your skin collagen breaks down, it shows up as wrinkles, fine lines, and other signs of aging[*]. Taking collagen may provide the raw materials to offset this decline. In one controlled study, collagen supplementation improved skin elasticity in 69 women aged 35 to 55[*].
  • Longevity: Diets rich in meat are rich in methionine, an amino acid which may — in excess —  accelerate aging. In mice, researchers have shown that supplementing with glycine (the main amino acid in collagen) mitigates the effects of methionine and extends lifespan[*]. 
  • Joint support: NSAIDs (non steroidal anti inflammatory drugs) are the standard treatment for chronic joint pain, but these medicines have bad side effects[*]. Enter collagen. In one study, collagen supplementation reduced activity-related joint pain in 97 college athletes[*]. 
  • Gut health: Collagen protein helps maintain the gut barrier, which breaks down (leaky gut) in those with chronic gut issues[*]. Clinical trials are lacking, but there’s no shortage of anecdotal evidence on bone broth for gut health.  

Amino Acids in Bone Broth

Recall that glycine, the most abundant amino acid in collagen, was shown to extend lifespan in mice[*]. Driving this effect, researchers believe, was glycine’s role in clearing methionine from the body. 

It’s possible, in fact, that glycine is the key to most of bone broth’s benefits. That’s because eating glycine may mitigate certain harms of the modern diet. 

Our ancestors used to eat animals from tip to tail — all that collagen-rich connective tissue. But now we only eat the lean parts. In other words, we’ve sacrificed glycine for methionine. 

We need to put that glycine back. And not just for a potential longevity benefit. 

You need, for instance, about ten grams of glycine per day for optimal collagen synthesis. However, you can only synthesize about 3 grams.[*

The rest must come through diet. Drinking a couple cups of bone broth per day will get you there. 

And glycine isn’t the only beneficial amino acid in bone broth. Bone broth is also rich in proline and hydroxyproline — both important inputs to collagen formation in your body. 

The bottom line? Bone broth is rich in beneficial amino acids —  like glycine — that are scarce in the modern diet. 

Sample Bone Broth Meal Plan

Here’s a sample bone broth diet plan for your five feeding days and two fasting days. (Note: these menus are both keto and paleo friendly). 

Sample Feeding Day (Five Days Per Week)

Breakfast: 3 egg omelette with full fat cheddar cheese, spinach, and side of pasture-raised bacon

Lunch: Fresh kale salad with olive oil, vinegar, almonds, and 6 ounces of wild caught salmon on top

Snack: 1 cup bone broth

Dinner: 6 ounces of grass fed steak, 1 avocado, 1 cup cooked shirataki noodles with olive oil and herb dressing, roasted asparagus, steamed broccoli

Sample Fasting Day (Two Days Per Week) 

Breakfast: 1 cup bone broth

Lunch: 1 cup bone broth

Snack: 1 cup bone broth

Dinner: 1 cup bone broth

Best Sources of Bone Broth

If you have time, you can make bone broth at home. Simply gather a mess of beef or chicken bones (a chicken carcass works well), add water and a teaspoon of vinegar, and let the pot simmer for 20-36 hours. 

Presto. Your very own bone broth. 

But maybe your schedule doesn’t have room for extended simmering. After all, making bone broth requires considerable time and effort. 

Not to worry, because you can buy high-quality bone broth at the store or online. 

Kettle & Fire is a good option. This company simmmers bones from organic chickens and grass fed cows for over 20 hours. 

It’s the real deal.

Can The Bone Broth Diet Be Keto?

On a bone broth fast, you’re supposed to eat paleo on feeding days. You might be wondering: Can I eat keto instead?

Yes. A bone broth fast is perfectly compatible with a whole foods ketogenic diet. Just make sure you’re eating about 60% fat, 30% protein, and 10% carbs on feeding days, with plenty of non-starchy veggies. 

The bone broth days stay the same. Just broth. 

The truth is, paleo and keto diets aren’t so different. The paleo diet allows more carbs, and sometimes disallows dairy — but both diets prohibit the processed junk that plagues the Standard American Diet. Also, both diets are keen on bone broth. 

To be clear, bone broth fasting isn’t specifically supported by published evidence. It does, however, combine intermittent fasting and collagen — both of which have been researched for their health benefits. 

If you give the bone broth diet a try, please share your experience in the comments. Thanks for reading. 

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