The ‘Eat Like a Bear’ diet promotes eating a single large, keto/low-carb meal each day and fasting for the rest of the day. The primary reported benefit of this diet is weight loss and secondarily, improved metabolic health.
‘Eat Like a Bear’ includes two main diet principles: intermittent fasting and keto/low-carb. These strategies both have health benefits but may not be right for everyone.
Overall, the ‘Eat Like a Bear’ diet is a more extreme approach to intermittent fasting and a keto/low-carb diet that I would not recommend as a clinician due to the possible risk of side effects.
Looking up recommended diets on the internet feels a bit like trying to tiptoe your way through a minefield. There are many popular diets that claim to be ideal for weight loss, metabolic health, fitness, or other health goals. Some of them may have merit, but many of them could actually slow down your healing progress.
At the Ruscio Institute for Functional Medicine, we teach all of our patients that a healthy, well-balanced, anti-inflammatory diet is one of the essential pillars of health. Without a healthy diet (along with sleep and movement), you can’t build a strong foundation for your long-term health and well-being.
That’s why I want to spend some time discussing these popular diets in a series called “diets debunked.” We’ll look at why some trending diets may be hindering your health goals — as well as what benefits and key ideas they might bring to the table that we can adapt to your nutritional needs and goals.
For our first deep dive into these popular diets, we’re talking about the ‘Eat Like a Bear’ diet. We’ll discuss the principles and goals of the diet, proposed benefits, what quality research exists around the diet, if any, what it gets right and wrong, and what parts of the diet we can implement for certain health goals.
What Are the Principles or Goals of the ‘Eat Like a Bear’ Diet?
The ‘eat like a bear’ diet was founded by a woman named Amanda Rose, who found that eating one extremely high-calorie meal per day over a period of an hour and fasting for the remaining 23 hours of the day helped her lose weight. Her educational background includes a PhD in political science. She attributes her weight loss success to her training as a social choice political scientist, and her biography on her website doesn’t include any nutrition-related credentials .
The premise of the diet is to “’eat like a bear’” by consuming food during a short window of time and fasting the rest of the day to promote weight loss. Amanda mentions in a video on her website that she lost over 100 pounds in 8 months by only eating during a one-hour window per day.She uses the analogy of a bear feasting on a meal and then going into hibernation mode, living off of its body’s stored fat. She says that humans can also burn stored fat by intermittent fasting each day.
According to Woman’s World magazine, Amanda first discovered this diet one day by sipping coffee until lunch-time, and then eating “the ridiculously big salad” that left her feeling full for the rest of the day. The salad contained lettuce, onion, tomato, bell peppers, grilled chicken breast, avocado, and homemade ranch dressing.
That evening, she felt tired and went to bed early without eating dinner. She then began eating this way every day, and if she ever felt hungry outside of her one meal, she would sip seltzer to quell her hunger. She says after a while, she began to have more energy and her knee pain went away, and she ended up losing 100 pounds in 30 weeks .
The diet follows two key tenets: intermittent fasting (time-restricted eating) and eating keto/low-carb meals .
For intermittent fasting, the ‘Eat Like a Bear’ website mentions eating within a limited block of time, such as a five-hour window.
For keto/low-carb, the website states that there are many different versions of the ketogenic diet and that it is best to “do what works for you.” Amanda mentions on the website that she doesn’t count her macronutrient intake and she doesn’t use precise portion sizes for protein and fat. She states that quick weight loss requires very low sugar and starch intake so that the body will burn fat.
Proposed Benefits of the ‘Eat Like a Bear’ Diet
This diet has no proven benefits because it has not been researched, but Amanda claims that it was the main factor that helped her lose a significant amount of weight. The ‘Eat Like a Bear’ website has success stories from people who say they also lost weight by eating this diet.
Proponents of the diet also claim that it is ideal for women over 50, a community that has sometimes been labeled as “unable” to lose weight, or at least for whom it is more difficult.
Is There Quality Research Backing the ‘Eat Like a Bear’ Diet?
There is no research backing the ‘eat like a bear’ diet specifically, but there is research on both intermittent fasting and the keto and low-carb diets. However, there is no significant research on any of these diets or eating patterns for long-term health and well-being and very little on the combination of IF and keto/low-carb.
Research-backed benefits of intermittent fasting include:
Improved metabolic health, weight loss, and heart health [4, 5, 6, 7, 8, 9]
These studies show that the benefits above are possible but not guaranteed for anyone who follows a keto/low-carb diet or does intermittent fasting.
Research also states that there are contraindications (reasons people should NOT do a health practice or procedure) for both intermittent fasting and keto diet/low-carb. Some of these contraindications include [22, 23]:
Being very old or very young
Having hormone imbalances
Working night shift
Operating heavy machinery
Having low blood sugar
Being pregnant or trying to get pregnant
Since ‘eat like a bear’ is targeted at women 50 and over, it’s also very important to note that research shows older people have higher protein requirements, and they must include enough protein during feeding windows to prevent muscle wasting [22, 24, 25].
What Risks Come with the ‘Eat Like a Bear’ Diet?
The ‘Eat Like a Bear’ website doesn’t seem to list any potential negative side effects or risks from the diet, but there are several concerns you should be aware of before trying this diet or any other type of intermittent fasting or keto/low-carb diet.
1. Low Blood Sugar
The first risk is the possibility of a sudden drop in blood sugar due to prolonged fasting when you’re not used to fasting for 23 hours a day. This can result in lightheadedness, dizziness, fatigue, and may even carry a risk of falling if you pass out.
While Amanda claimed she was able to completely transition to this eating pattern in one day and then maintain it from that day forward, this will not be the case for everyone. Many people cannot tolerate longer periods of fasting well right away, especially with zero fasting experience. And others simply need more regularly spaced meals throughout the day to keep their blood sugar balanced and energy up.
2. Nutrient Deficiencies
Another risk is becoming deficient in one or more micronutrients when you’re only eating one meal a day with a limited number of foods, regardless of how large that meal is. Additionally, many people may underestimate the amount of carbohydrates they actually need when following a keto or low-carb diet. Many women find they need more carbs to support hormone production and energy, pre- or post-menopause.
Amanda herself noted that she did not track her macronutrients or stick to a specific ratio of protein, carbs, and fats and encourages people to “do what works for them.” But this lack of guidance leaves more room for nutrient deficiencies to occur on the ‘eat like a bear’ diet.
3. Keto flu
Another possible risk is a side effect of keto/low-carb called the “keto flu” — experiencing flu-like symptoms for a period of days to weeks when first starting the keto diet. Symptoms may include:
Poor exercise tolerance
It’s not known exactly what causes a keto flu, but it may be a kind of Herxheimer reaction, which is essentially an immune response caused by rapid detoxification in the body, in this case, initiated by the change in diet. This is just one possible theory. In either case, there is no need to continue the keto diet if you have a reaction like this lasting longer than 2-3 weeks.
4. Other issues
Some rare but more serious possible long-term effects of the keto diet include :
Fat buildup in the liver (known as hepatic steatosis)
Low protein in the blood (known as hypoproteinemia)
Vitamin and mineral deficiencies
If you are on a keto diet already, this isn’t cause for alarm, it just means you should be working closely with your doctor to monitor these potential risks.
What Does the ‘Eat Like a Bear’ Diet Get Right?
Intermittent fasting and keto are totally valid diets when done correctly and with periodic monitoring to make sure all your nutrient needs are being met. But it is still unclear what long-term effects these diets have over a period of several years and beyond.
Intermittent fasting has been shown to have metabolic benefits, improving obesity, type 2 diabetes, heart disease, and systemic inflammation . IF may even have gut-related benefits as well, improving gut microbiome composition, supporting gut wall integrity, and reducing IBS symptoms [13, 14, 16, 17].
Keto was originally developed as a brain-supportive diet for epilepsy patients , but it too has been shown to support metabolism, insulin resistance, type 2 diabetes, and other conditions .
There’s also nothing wrong with reducing your calorie intake if you are trying to lose weight and you know you’re consuming too much. But suddenly cutting your calories in half or more and eating only one meal a day may put undue stress on your body.
What Parts of the ‘Eat Like a Bear’ Diet Can We Implement and How?
There are a few elements of the Eat like a Bear Diet that may be helpful for some people:
Consider intermittent fasting. If your goal is to lose weight, many people have found great benefit from intermittent fasting for this purpose. If you’re curious about the effects of intermittent fasting, you can start out with a 14:10 or 16:8 schedule instead of a 1:23 schedule. Most people find a 10 or 8-hour eating window to be manageable, and they will get similar metabolic benefits to a longer fasting period. Intermittent fasting alongside the Paleo diet can be a great way to get started with IF for many people.
Increase your healthy fat intake. Incorporating more healthy fats in your diet and slightly lowering carb intake, especially if you are reaching for processed foods on a daily basis, is also not a bad idea. More healthy fats, like olive oil, coconut oil, avocado, and even grass-fed ghee and butter in moderation, can increase satiety and keep you fuller for longer, preventing you from reaching for the bag of chips or sweet treats.
Increase your fiber intake. Increasing your fiber intake, as long as you don’t have gut issues that would prevent good digestion, will have a similar effect of keeping you full throughout the day. It doesn’t have to be a ridiculously big salad, but adding an extra serving of veggies to your meals usually doesn’t hurt.
Should You Try the ‘Eat Like a Bear’ Diet?
The ‘Eat Like a Bear’ diet is a combination of intermittent fasting and keto/low-carb dieting that is supposed to result in significant and relatively fast weight loss. However, it is a pretty extreme form of intermittent fasting with only one large meal per day and fasting for the remaining 23 hours. This leaves room for several complications, including nutrient deficiencies, low blood sugar during the fasting period, low energy, hormone imbalances, and more.
As a clinician, I would not recommend trying this diet. Instead, you can try less extreme forms of intermittent fasting like the 14:10 or 16:8 patterns that allow for at least two full meals a day and probably one or two snacks that would allow you to meet all of your nutritional needs and feel satisfied with your meals.
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