Truth About the Keto Diet, According to Science
About 45 million Americans go on a diet every year. We shell out billions of dollars for products and plans that claim to help us fit in the jeans we wore in high school — about $33 billion dollars, to be exact. The only problem? Most diets don't work.
The ketogenic diet, also known as keto, has made waves due to its reputation for helping people shed pounds fast. But is the keto diet healthy for everyone or another crash diet? We asked Dr. Lucia Aronica to clear up the confusion once and for all.
Dr. Lucia Aronica is a lecturer at the Stanford Prevention and Research Center within the Stanford University School of Medicine.
What Is the Keto Diet Anyway?
For years, low-fat diets were promoted as the best option for weight loss. If you eat less fat, you won't gain as much, right? Unfortunately, we were totally wrong about that. Our bodies are pretty smart. While most of us prefer muffin tops as a treat, not around our waists, that extra fat has a purpose: survival.
Our ancestors didn't have a Trader Joe's down the street. When food was plentiful, we ate more of it. The excess energy was stored as fat, which helped us survive famines down the line. The same metabolic mechanisms exist, but most of us are lucky enough to never experience a serious food shortage.
The downside is that if we continuously consume more calories than our bodies use, we continue building fat reserves that we don't actually need. While simply reducing calorie intake is enough to force our bodies to use stored fat for energy, what you eat is just as important as how much. When we consume plentiful carbs, like those found in bread, pasta and fruit, our glucose levels rise. That glucose is then used as fuel.
On a ketogenic diet, however, carbohydrate intake is drastically reduced, with a high fat intake and a moderate protein intake. With little available glucose, your body uses stored fat as backup fuel instead. Effectively, it mimics the effects of fasting without actually doing so.
Switching From Glucose to Fat As Body Fuel
Just as a car needs gas to run, your body needs fuel to run. The better fuel (food) you put in your body, the better your body will function. This is how fast mimicking works.
"Ketosis is the hallmark of fasting and a common feature of most fast-mimicking diets" explains Dr. Lucia Aronica. "Fast-mimicking diets are diets that reproduce, mimic the effects of fasting by inducing a metabolic switch from using glucose to using fat as fuel. And in this process, we break down body fat and turn it into ketones, which are miniature fatty acids that can cross the blood-brain barrier and provide a fuel for the brain when blood glucose is low. And we don't either receive carbohydrates or we fast.
"Understanding the link between fasting and ketogenetic diets can help us debunk the myth that ketosis is an unnatural and dangerous state."
Fasting Turns on Ancestral Survival Pathways
Fasting goes way back in human evolution. Long before supermarkets, refrigerators and year-round food availability, humans learned to live without food for long periods.
So a fasting diet, such as keto, comes from our deep evolutionary past.
Keto Began As an Epilepsy Treatment
Originally, the ketogenic diet wasn't about weight loss at all. It was discovered in the 1920s that an extremely low-carbohydrate diet drastically reduced the frequency of seizures in patients with epilepsy. It became a standard treatment for the disorder until new anticonvulsant therapies were introduced in the 1940s.
Since a strict ketogenic diet was often challenging for children with epilepsy to follow, medication was a preferable option. In instances where seizures were still poorly controlled by medication, the diet was reintroduced to achieve better results.
It was later discovered that a ketogenic diet had numerous benefits beyond epilepsy management, and efforts were made to create keto-friendly options that were actually tasty.
Who Is a Ketogenic Diet Meant For?
The ketogenic diet isn't for everyone, but it's worth considering for a number of reasons. It's not the only way of losing weight, but the way your body responds to keto often results in a naturally reduced appetite. Keto fans report feeling full for longer, making it easier to avoid snacking throughout the day.
It's also a good option for anyone with a family history of heart problems, dementia and certain cancers, as some studies show that keto helps stave off these conditions.
Your genes may influence how you respond to a keto diet. Only a few genetic markers have been verified to influence one's response to a ketogenic diet, but research does give indications that some people may lose weight faster or see more health benefits than others.
Pros and Cons
There are numerous benefits to eating a ketogenic diet, including:
- Weight loss
- More sustainable weight maintenance
- Fewer breakouts
- Improved cholesterol levels
- Improved brain function
- Improved blood sugar levels
- A lowered risk of developing type-2 diabetes
- Reduced PCOS symptoms in women
Some of these benefits, however, depend on the quality of the food consumed on a ketogenic diet. Just cutting out carbs won't help you avoid cholesterol meds unless your keto plan is full of nutritionally balanced whole foods, too.
There are some downsides to keto, however, and it may not be right for everyone. People who should avoid a strict keto diet include:
- Women who are pregnant or nursing
- Anyone with kidney, liver, or pancreas issues
- Anyone who's undergone gallbladder removal
- Anyone with a history of eating disorders
- People with type-1 diabetes
Even people who are completely healthy may experience some initial side effects, colloquially referred to as the "keto flu." While adjusting to keto, some people experience:
- Fatigue and less exercise tolerance
- Low blood sugar
Once your body adjusts to burning fat for fuel instead of using glucose, symptoms fade or go away entirely.
Does Only Strict Keto Work?
If you want to reap the full benefits of the keto diet, eating a clean keto diet full of highly nutritious foods is the best option. Sticking with an ultra strict way of eating all the time isn't always realistic. We get it.
Dirty keto is an option that allows more "junk" foods, as long as they're low in carbs. These are some dirty keto options:
- Processed oils and proteins
- Artificial sweeteners
- Low-carb snack foods
- Coffee and tea beverages using coconut milk and sugar-free syrup
- And anything else low-carb that isn't exactly a nutritionist's dream
For example, a cheeseburger with a keto-friendly bun qualifies as a dirty keto meal, even though the quality of the ingredients isn't amazing. Mixing in dirty keto days can make the diet more sustainable in the long run. Many people, however, stop craving junk food the longer they're on a nutrient-rich keto diet.
Foods You Can Eat on the Keto Diet
The keto diet may appear challenging, but there are many low-carb, nutritious foods you can eat on it.
Meat, Poultry, Eggs
- Any types of eggs
- Bacon and sausage (in moderate amounts)
- Artic char
Lean Fish/Seafood That Need More Fat on Keto
- Tuna (yellowfin)
- Tuna (canned)
- Green beans
- Bell peppers
- Yellow squash
- Spaghetti squash
- Brussel sprouts
- Any hot peppers (jalapeno, poblano, habanero)
- Baby spinach
- Bok choy
- Collard greens
- Mustard greens
- Swiss chard
- Blue cheese
- Colby jack
- Cottage cheese
- Cream cheese
- Goat cheese
- Pepper jack
- String cheese
- Swiss cheese
Nuts and Seeds
- Brazil nuts
- Macadamia nuts
- Chia seeds
- Pumpkin seeds
- Sesame seeds
- Unsweetened coffee
- Black or green tea
- Herbal tea
- Almond or coconut milk (unsweetened)
- Macadamia nut milk
- Flaxseed milk
- Some diet sodas
- Sparkling water
- Lemon and lime juice
- Vegetable juice (celery, cucumber, kale, spinach)
- Naturally derived energy drinks (EBoost, Kill Cliff)
- Low-carb beer
- Hard liquor (vodka, whiskey, rum, tequila)
- Low-carb hard seltzer
Foods You Should Avoid on the Keto Diet
The keto diet is about total carbohydrate intake and how you want to "spend" your carbs. Therefore, you can think of your glycogen as a checking account, which is easily accessible but has limited funds.
By the same analogy, your body fat can be viewed as a savings account, which has plenty of funds but is more difficult to access. We need to either fast or restrict carbohydrates to access them through the production of ketone bodies.
While no foods are off-limits on the keto diet, it is best to avoid these foods.
- Baked goods (including gluten-free baked goods)
- Sweet potato
- Acorn squash
- Butternut squash
- Onions (in large amounts)
- Sweetened yogurt
- Sugar in any form
Plenty of Big Name Stars Swear by Keto
Our main focus at FamilyMinded is on promoting healthy living. How your diet affects how you feel is the most important part. If you care about aesthetic benefits, however, there's plenty of evidence that keto can help you bring out your natural glow.
Tons of A-listers have adopted a ketogenic diet, including Halle Berry, Kourtney Kardashian, Vanessa Hudgens and LeBron James. Weatherman Al Roker tried it too, and claims he feels much better since he started it.
Real Science Behind the Keto Diet
Keto can be good for you for many reasons. Stanford University researchers Dr. Lucia Aronica and Dr. Shebani Sethi Dalai delved deep into the science behind ketogenic diets during a discussion with Silvia Segerstrale, a wellness educator and nutrition consultant at Stanford Concierge Medicine.
Dr. Lucia and Dr. Shebani examined the promises, perils and practical clinical aspects of the keto diet. But the bottom line is that people must do what is best for them.
"It is important to move away from polarization toward personalization in nutrition and challenge one-size-fits-all- truths," says Dr. Lucia. "We need to find individual answers to live life at the fullest. And we need to work together to make personalized nutrition a reality. We need to be humble, skeptical, proactive and optimistic.
"Humble. As the philosopher Socrates said more than 2,000 years ago, the science is less about having the answers and more about looking for them.
"Skeptical in knowing what works for some people may not work for other people.
"Proactive in educating ourselves, experimenting, self-experimenting. Monitoring ourselves and engaging in our own health decisions.
"And most of all, optimistic. Because if we don't believe we can change ourselves and the world around us, we won't."
How to Give Keto a Try
If you have no pre-existing conditions and aren't pregnant or breastfeeding, it's most likely safe to try keto on your own. It doesn't hurt to check with your doctor first, though.
Once you have a green light, aim to eat a diet composed of 60-80 percent healthy fats, 10-30 percent protein, and only 5-10 percent carbs. Depending on your daily calorie intake, this equates to 20-50 grams of carbohydrates per day.
To achieve this, look for foods high in fat. Good examples include:
- Seafood, especially salmon and other fish
- Meat and poultry
- Plain Greek yogurt
- Most leafy greens
- Very dark chocolate — at least 70 percent cocoa solids
"Food is not only calories," says Dr. Lucia. "It is biological information. It is the most powerful signal to our genes. The most powerful way of transforming our health. From the inside out."
FamilyMinded is partnering with Dr. Lucia Aronica for health and wellness news. To learn more about how you can take control of your health using science, check out Dr. Lucia's free webinar, her website and YouTube channel.
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