To say that the keto diet has become one of the most popular diets of recent years is a complete understatement. Case in point: There are more than one million searches on Google every month for the keto diet. It’s unique because the fat diet has captured the interest of people who want to lose weight — and there’s no shortage of reported success stories to be found.
But researchers have taken a greater interest in it as a medical diet, too. In 2015, there were 159 studies listed in the database PubMed (which is run by the U.S. National Library of Medicine and the National Institutes of Health). In 2018, that number doubled, with 322 published studies.
- The Keto Diet, Defined: A Brief Primer
- A Glance at What Eating on the Keto Diet Looks Like
- What a Day of Eating Looks Like on a Keto Meal Plan
- Benefits of Eating a KETO DIET:
- Focusing the brain (increased memory, cognition, clarity, and seizure control; less migraines)
- Preventing Heart Disease (lower blood pressure, lower triglycerides, better cholesterol profiles)
- Decreasing inflammation (which improves acne, arthritis, eczema, psoriasis, IBS, pain, etc…)
- Improving energy levels and sleep
- Keeping uric acid levels in check (helping kidney function and preventing gout)
- Assisting gastrointestinal and gallbladder health (less heartburn and acid reflux, less risk for gallstones, improved digestion, less gas and bloating)
- Assisting Women’s Health (increased fertility, stabilizing hormones)
- Helping the eyes (more stable vision; less risk for cataracts)
- Gaining muscle and improving endurance
- And last but not least, curbing diabetes, obesity, and metabolic syndrome while sparing muscle loss
The Keto Diet, Defined: A Brief Primer
So what is the keto diet?
The diet calls for consuming high amounts of fat, a moderate amount of protein, and a very limited amount of carbs. It’s usually broken down to 75, 20, and 5 percent of your daily calories, respectively, says Pamela Nisevich Bede, RD, a dietitian with Abbott’s EAS Sports Nutrition in Columbus, Ohio. Compare that with the typical American diet — which is usually 50 to 65 percent carbs — and it’s safe to say this is a completely different way of eating, Nisevich Bede says.
After you follow the diet for a few days, your body enters ketosis, which means it has started to use fat for energy. Newbies on the diet find it helpful to track whether they’re in ketosis with a urine ketone strip or a blood-prick meter, but Nisevich Bede says you’ll eventually learn what ketosis feels like and will know whether you’re in it.
A Glance at What Eating on the Keto Diet Looks Like
The keto diet is all about increasing calories from fat and going very low carb. That means following a restrictive, keto-friendly food list.
Here are some of the foods you may eat on keto:
- Oils (like olive oil, avocado oil, and coconut oil)
- Heavy cream
- Cream cheese
- Coconut (unsweetened)
- Nuts (almonds, macadamia) and seeds (chia seeds, flaxseed, sunflower seeds)
- Leafy green vegetables (romaine, spinach, kale, collards)
- Nonstarchy vegetables, including zucchini, asparagus, cucumber, broccoli, cauliflower, and bell peppers
- Meats (chicken, beef, pork, lamb)
- Fish (particularly fatty fish like salmon and sardines)
What You Can’t Eat (or Drink) on the Keto Diet
Foods and drinks that you’ll avoid on the keto diet include many whole fruits (though some fruits are keto-friendly), dried fruits, whole grains, cold cuts, chicken nuggets, milk, ice cream, alcohol, and desserts.
What a Day of Eating Looks Like on a Keto Meal Plan
Breakfast Two fried eggs, tomato slices, coffee with heavy cream
Snack Full-fat cottage cheese topped with pine nuts
Lunch Spinach salad with a grass-fed burger on top, cheese and avocado
Snack Roasted, salted almonds
Dinner Grilled salmon with a side of broccoli topped with butter
Benefits of Eating a KETO DIET:
Focusing the brain (increased memory, cognition, clarity, and seizure control; less migraines)
Ketogenic diets were notably first used at the Mayo Clinic in the 1920s to treat children with epilepsy. While the exact mechanism of seizure prevention on a ketogenic diet is still a mystery, researchers believe it has something to do with the increased stability of neurons and up-regulation of brain mitochondria and mitochondrial enzymes.
Related to this research, some serious attention has been given to ketogenic dieting and Alzheimers Disease. Scientists have discovered increased cognition and enhanced memory in adults with impairments in these areas, and a growing body of research shows improvement at all stages of dementia. Ketosis has been shown to be effective against Parkinson’s disease as well.
Preventing Heart Disease (lower blood pressure, lower triglycerides, better cholesterol profiles)
Again, related to the downstream effects of keeping blood glucose low and stable, ketogenic dieting helps keep blood pressure in check and lowers triglyceride levels.
While it may seem counterintuitive that eating a higher percentage of fat in your diet lowers triglycerides, it turns out that the consumption of excess carbs (especially fructose) is the key driver of increasing triglycerides.
And regarding HDL and LDL particles (which the body uses to move fat and cholesterol around), ketogenic dieting helps raise HDL (“good cholesterol”) and improve the profile of LDL (“bad cholesterol”).
Decreasing inflammation (which improves acne, arthritis, eczema, psoriasis, IBS, pain, etc…)
A Nature Medicine article last year found a likely mechanism behind what people have known for decades: ketogenic dieting is profoundly anti-inflammtory and helps with a host of related health problems.
The researchers found that “the anti-inflammatory effects of caloric restriction or ketogenic diets may be linked to BHB-mediated inhibition of the NLRP3 inflammasome.”
In other words, the key player in many inflammatory diseases is suppressed by BHB, which is one of the main ketones produced from a ketogenic diet.
Thus the implications on arthritis, acne, psoriasis, eczema, IBS, and other diseases involving inflammation and pain are significant enough that it is prompting more research attention.
Improving energy levels and sleep
By day 4 or 5 on a ketogenic diet, most people report an increase in general energy levels and a lack of cravings for carbs. The mechanism here involves both a stabilization of insulin levels and readily available source of energy for our brain and body tissues.
Sleep improvements are a bit more of a mystery. Studies have shown that ketogenic dieting improves sleep by decreasing REM and increasing slow-wave sleep patterns. While the exact mechanism is unclear, it likely is related to the complex biochemical shifts involving the brain’s use of ketones for energy combined with other body tissues directly burning fat.
Keeping uric acid levels in check (helping kidney function and preventing gout)
The most common cause of kidney stones and gout is elevated uric acid, calcium, oxalate, and phosphorus levels as result of a complex combination of unlucky genetics, dehydration, obesity, sugar consumption (especially fructose), and eating/drinking things with a lot of purines and alcohol (e.g. meat and beer).
An important caveat is that ketogenic diet temporarily raises uric acid levels — especially when dehydrated — but over time they come down:
…uric acid goes up promptly in the same time frame that ketones go up, but after 4–6 weeks, despite ketones staying up, uric acid starts to come back down. Based on these data and my clinical observations in thousands of patients, uric acid returns to or below pre-diet baseline within 6–12 weeks despite the person remaining is a state of nutritional ketosis.
Assisting gastrointestinal and gallbladder health (less heartburn and acid reflux, less risk for gallstones, improved digestion, less gas and bloating)
It is well known that grain-based foods, nightshade vegetables like potatoes and tomatoes, and sugary foods increase the likelihood of acid reflux and heartburn. Therefore, it’s not surprising that eating a low-carb diet improves these symptoms and actually confronts the root problems of inflammation, bacterial issues, and autoimmune responses.
Related to this, it is known that changes in diet rapidly and reproducibly alters the human gut microbiome. Dr. Eric Westman describes at length how a host of problems are significantly reduced or removed as a result of microbiome changes on a ketogenic diet.
Assisting Women’s Health (increased fertility, stabilizing hormones)
An extensive review published in 2013 looked at the research and evidence of ketogenic diets enhancing fertility (long story short, it looks promising). Studies also show that Polycystic Ovary Syndrome (PCOS) can be treated effectively with low-carb dieting, which reduces or eliminates symptoms such as infrequent or prolonged menstrual periods, acne, and obesity.
Overall, keeping blood sugar levels low and stable, which results in lower overall levels of insulin in the blood, helps equilibrate and stabilize other hormone levels, especially in women. This naturally has downstream benefits on a wide variety of metabolic pathways related to insulin, such as hunger and energy utilization.
Helping the eyes (more stable vision; less risk for cataracts)
As any diabetic will tell you, it is well known that high blood sugar has a detrimental effect on eyesight and leads to an increased risk for cataracts. It’s therefore not surprising that keeping blood sugar levels low improves eye and vision health, as a gazillion people have shared online, and as related diabetes research has proven.
Gaining muscle and improving endurance
BHB, specifically, has been shown to promote muscle gain. Combined with tons of anecdotal evidence over the years, there is an entire movement behind bodybuilders using a ketogenic approach to gain more muscle and less fat (typically muscle gain also comes with fat gain, so there’s understandable attention being given toward preventing this).
In addition, Dr. Stephen Phinney and Dr. Jeff Volek have a number of papers published about ketogenic dieting for ultra-endurance athletes. In short, once these athletes are fully fat-adapted, there is evidence to suggest that mental and physical performance is significantly improved beyond a “normal” carbohydrate-rich diet.
And last but not least, curbing diabetes, obesity, and metabolic syndrome while sparing muscle loss
Of course, there are over 160 research papers currently on Pubmed with the words “diabetes” and “ketosis” or “ketogenic” in the title alone. It’s beyond clear that ketogenic dieting is extremely effective for many people with both type I and type II diabetes for all the reasons discussed above related to keeping blood sugar levels and insulin in check.
What Are the Potential Health Risks Associated With the Keto Diet?
The possible benefits of the diet are impressive, but there are a few potential downsides to note. One is it’s tough to stick to. In fact, in a review of 11 studies involving adults on the keto diet, which was published in January 2015 in the Journal of Clinical Neurology, researchers calculated a 45 percent compliance rate among participants following the approach with the aim of controlling epilepsy. “The diet is pretty hard to follow because it’s a complete shift from what you’re used to,” Nisevich Bede says. Slashing your intake of carbs can also make you feel hungrier than usual — a feeling that can last until you’re three weeks in.
It’s also common for people starting the diet to experience flu-like symptoms, such as headaches and fatigue. This side effect is so common that there’s a name for it: the keto flu. “You shed a ton of water weight at first, which can lead to dehydration,” Nisevich Bede explains. This can worsen the symptoms of the keto flu. To counter it, she recommends staying hydrated and loading up on electrolytes through electrolyte tablets.
Other potential risks include kidney stones, several vitamin and mineral deficiencies, decreased bone mineral density, and gastrointestinal distress. (7)Here’s why: When you’re eliminating certain food groups (like fruits, legumes, and whole grains) and severely limiting others (like many vegetables), it’s not uncommon to experience nutritional deficiencies. A lack of fiber, for instance, can make it more likely you’ll experience constipation.
In order to avoid some of these risks, the diet needs to be well planned to ensure you’re hitting all of your nutritional bases. Unfortunately, a restrictive diet makes this planning a challenge, especially if you’re not working with a registered dietitian who is knowledgeable in keto.
People Who Should Avoid the Keto Diet
Despite claims that the keto diet can help the following groups, experts say the plan may be risky for them:
People With Type 1 Diabetes These individuals are insulin-dependent, and a keto diet could lower their blood sugar to dangerous levels, says Moree.
People With a History of Eating Disorders Going on a strict diet that eliminates food groups could trigger a relapse if you have a personal history of having an eating disorder. And while there’s a growing popularity in treating binge eating disorder (BED) with keto, experts strongly advise against it. Treatment of BED requires regular, adequate food intake without restriction, says Sumner Brooks, MPH, RDN, a certified eating disorder dietitian in Portland, Oregon.
People Who Have Had Their Gallbladder Removed A gallbladder holds bile, which aids in fat digestion. Without this organ, you will not feel your best on a high-fat diet.
People With Thyroid Disease A a keto diet may suppress levels of thyroid hormones, says Audrey Fleck, RDN, an integrative and functional nutritionist and certified diabetes educator in Perkasie, Pennsylvania. That means the diet has been touted as a treatment for hyperthyroidism; nonetheless, the approach is controversial.
People With Multiple Sclerosis (MS) The National Multiple Sclerosis Society raises questions about the long-term safety of the diet for MS, and cautions about the possible side effects, like fatigue and constipation.