Is the Ketogenic Diet All it's cracked Up to Be? -

Kaitlin Little

Despite decades of dietary guidelines promoting a low-fat diet rich in “heart healthy” grains, over 70% of the adult population in the United States is now either overweight or obese. [1] Not to mention, at least 6 in 10 American adults now have a chronic diet-related disease, such as heart disease, stroke, cancer, or diabetes. [2]

Clearly eating a low-fat diet is not the entire answer. In fact, some studies suggest the exact opposite may be true.

With a better understanding of the role that sugar and refined carbohydrates play in chronic disease, researchers have turned their attention to the ketogenic diet, which embraces healthy fats and strictly limits carbohydrates.

So maybe the Ketogenic Diet is, in fact, all it’s cracked up to be.

What is the Ketogenic Diet?

The ketogenic diet (also known as the keto diet) is a low- carbohydrate, high-fat diet with an impressive list of potential health benefits. It involves minimizing carbohydrate intake and maximizing fat intake in order to induce ketosis.

Ketosis is a metabolic state during which the body burns fat as the primary fuel, instead of carbohydrates. The word ketosis comes from ketones, which are small molecules formed when the body is forced to burn fat because carbohydrates are low.

How Does Ketosis Work?

Cut Carbs: The ketogenic diet starves the body of carbohydrates and provides moderate amounts of protein. As a result blood glucose levels and stored glycogen levels are depleted, and the body is forced to search for alternative fuel—fat.

Burn Fat: Under these circumstances, the liver converts fatty acids into acetyl-CoA, which is then transformed into ketones. They can then diffuse into the bloodstream and act as an alternative energy source for the body and brain.

Fuel with Ketones: Just like glucose, ketones provide cells with ATP. ATP is a high-energy molecule that drives all cellular processes within the body, from muscle contractions and nerve impulses to protein synthesis needed for growth.

On the ketogenic diet, the body becomes highly efficient at burning fat, which can be very beneficial when trying to lose weight.

Does the Ketogenic Diet Aid Weight Loss?

Over the last two decades, an increasingly large body of evidence has mounted to support the role of the ketogenic diet in weight loss.

In fact, the ketogenic diet may be superior to the low-fat diet. In a recent systematic review of 11 high-quality clinical trials, researchers found that a ketogenic diet helped patients lose an average of 4.8 lbs more than a low-fat diet. [3]

One clinical trial found that obese individuals on a ketogenic diet lost almost twice as much fat mass as those on a typical low-fat diet (21 lbs vs. 11 lbs). In addition, serum triglyceride levels decreased, and HDL “good” cholesterol increased more on the ketogenic diet. [4]

Another meta-analysis of 13 clinical trials, also confirmed that greater weight loss is achieved on a ketogenic diet than on a low-fat diet, but concluded that weight loss peaks after 5 months and is often not sustained once an individual returns to their regular diet. [5]

The ketogenic diet has also proven very effective at improving body composition, in particular reducing abdominal fat in both men and women. Abdominal fat is associated with visceral fat, which tends to accumulate around the internal organs and is linked to an increased risk of metabolic disease.[6]

Why Does the Ketogenic Diet Aid Weight Loss?

There are several reasons why maintaining a ketogenic diet can facilitate weight loss:

Suppresses Appetite

Ketogenic diets reduce your appetite mostly due to the satiety effect of fat and protein, but also due to changes in appetite-regulating hormones. [7] The hunger-promoting hormone, ghrelin, is suppressed during ketosis. [8]

Fewer Calories Consumed

Despite a high-fat content, ketogenic diets tend to decrease calorie intake when compared to high-protein and balanced diets. [9] [10] However, some research suggests ketone bodies (KB) might actually increase food intake through AMP-activated protein kinase (AMPK), a molecule that activates glucose and fatty acid uptake when energy levels are low. [11]

Higher Adherence

Hunger is often the worst side effect of dieting and the main reason people eventually give up. As the keto diet is typically more filling and satisfying, people tend to have fewer relapses and adhere to the diet for longer. [4] In fact, multiple studies have shown a higher retention rate for those on a keto diet compared to a low-fat diet. [4]

Improves Insulin Sensitivity

Once the body enters ketosis, insulin sensitivity improves, and blood glucose levels stabilize leading to more consistent energy levels.

Reduces Fat Storage

As the ketogenic diet is low in carbohydrates, it reduces lipogenesis, which is the conversion of glucose (blood sugar) into fatty acids for storage within fat cells. However, over-consumption, regardless of macronutrient balance, ultimately leads to lipogenesis and the formation of fat cells. [12]

Increases Gluconeogenesis

Low-carb diets induce gluconeogenesis, the creation of glucose from protein or fat. Converting protein and fat into glucose for energy is an ‘expensive’ process that requires additional calories, and may, therefore, burn more calories, aiding weight loss

Increases Energy Expenditure

Research suggests low-fat diets slow metabolic rate by more than 400 calories per day, while ketogenic diets only slow metabolic rate by around 140 calories per day. In other words, you can burn more calories while resting and during exercise on the ketogenic diet. [13] One potential explanation for this is increased gluconeogenesis.

What are the Health Benefits of a Ketogenic Diet?

Besides facilitating weight loss, the ketogenic diet offers a range of potential health benefits such as:

May Help Reduce the Risk of Cardiovascular Disease

Ketogenic diets have been shown to improve several biomarkers for heart disease and stroke, including a reduction in blood triglycerides by an average of 33% and an increase in “good” HDL cholesterol by 11%. [14] Interestingly, a systematic review of eight clinical trials also found ketogenic diets to be superior at reducing “bad” LDL cholesterol when compared to a low-fat diet. [15]

Furthermore, ketogenic diets may increase the size and volume of “bad” LDL cholesterol particles, which is believed to reduce the risk of heart disease and stroke, as smaller LDL cholesterol particles are more likely to cause atherosclerosis. Atherosclerosis is the narrowing of arteries from the the buildup of cholesterol and fatty deposits in the arterial walls.

May Help Improve Blood Sugar Control in Type II Diabetes

Diabetes is characterized by poor blood glucose regulation due to insulin resistance, or an inability of the pancreas to produce insulin. Higher levels of ketones have been shown to improve blood glucose regulation in people with diabetes by increasing insulin sensitivity.

One study prescribed obese patients with type II diabetes a ketogenic diet, which dramatically improved insulin sensitivity by 75% and reduced blood glucose levels within just two weeks. [16] In another study, 95% of diabetics placed on a ketogenic diet were able to stop or reduce their diabetic medication and lost 6% more body fat than those on a higher carbohydrate diet. [17]

May Help Reduce Seizures in Epileptics

The ketogenic diet has been used to as an effective treatment for severe childhood epilepsy since the beginning of the 20th century, with a recent Cochrane review demonstrating a 30-40% reduction in seizures comparable to conventional medications.

Although the mechanism of action is unclear, it is believed higher levels of ketones within the bloodstream have a direct anticonvulsant effect by reducing the excitability of nerves.

Emerging evidence:

There is evidence to suggest a ketogenic diet may provide benefit in the following conditions:

Cancer: The ketogenic diet is currently being used as an adjuvant therapy in cancer patients and shows promise for reducing the progression of brain tumors. [18]

Acne: Low-carb ketogenic diets reduce insulin levels, which can have a positive effect on acne-causing androgen hormones, including testosterone and insulin-like growth factor-1. [19]

Polycystic Ovary Syndrome: Research shows that ketogenic diets can reduce symptoms of polycystic ovary syndrome, by decreasing testosterone and insulin levels. [20]

Alzheimer’s: Ketogenic diets may reduce memory loss in Alzheimer’s disease and slow its progression. [21]

Formulating a Healthy Ketogenic Diet for Weight Loss

The ketogenic diet involves obtaining roughly 65-70% of your total daily calorie intake from fat, 25-30% from protein and just 5-10% from carbohydrates. To increase your chances of success, it is highly recommended that you work with a registered dietitian. He or she will help determine the precise quantity of each macronutrient, in grams, needed to safely lose weight, taking into account your sex, age, height, weight, medical history, and physical activity level.

As a general rule, healthy individuals can start by limiting daily carbohydrate intake to 50 grams, and replacing calories with large amounts of fat and moderate amounts of protein. However, you must choose your fat wisely! The importance of incorporating “healthy” fats cannot be emphasized enough. You can reach ketosis (and even lose weight) by consuming loads of full-fat cream, cheese, bacon, and artificial sweeteners — simply due to reduced carbohydrates. However, overloading on these “unhealthy” fats is detrimental to your health. Trans fat found in fried foods, baked goods, and processed snack food can elevate low-density lipoproteins (LDL cholesterol), which increases your risk for cardiovascular disease. [22]

On the other hand, a diet high in plant-based monounsaturated (found in avocado, almonds, cashews, olive oil) and polyunsaturated fats (found in salmon, sardines, canola oil, walnuts) is known to have a protective effect against cardiovascular disease. Replacing unhealthy fats with these healthy fats can decrease blood pressure, reduce low-density lipoproteins (e.g. “bad” cholesterol) and increase high-density lipoproteins (e.g. “good” cholesterol). [23] In contrast, trans fats can increase inflammation and are linked to multiple diseases, including heart disease, certain cancers, diabetes, and Alzheimer’s disease. [24]

As a beginners guide, a healthy ketogenic diet should incorporate the following:

Grass-fed meat and poultry
Fresh fish and seafood
Eggs
Non-starchy vegetables grown above the ground
Natural plant-based fats and oils
Nuts and seeds
Water, tea, coffee, and bone broth

It is essential that you drink plenty of water—at least 2 liters per day—to replace the lost water you would usually obtain from a diet high in carbohydrates.

While not a definitive list, you should avoid the following foods on a ketogenic diet:

Pasta, bread, rice, and noodles
Cakes, donuts, pastries, biscuits, and crackers
Candy and chocolate bars
Starchy vegetables grown below the ground e.g. potatoes, pumpkin, leek
All fruits, except small amounts of berries
Alcohol, juice, soda, and milkshakes
Dairy products, other than grass-fed butter or ghee, are generally not recommended, as dairy is known to cause inflammation. [25]

Choosing the correct foods to eat on the ketogenic is key to your success. A poorly formulated ketogenic diet can be high in unhealthy saturated and trans fats, low in dietary fiber, and missing some essential vitamins (thiamin, riboflavin, niacin, and folate) and minerals (iron and magnesium).

What to Expect on the Ketogenic Diet?

The typical American diet includes 200-350 grams of carbohydrates per day, while a ketogenic diet reduces carbohydrate intake to only 20-50 grams per day. That’s the equivalent of just ½ cup of pasta, 1 small potato, or a full plate of non-starchy vegetables.

This dramatic reduction in carbohydrates does not come without drawbacks. In fact, most people feel unwell for the first week or two as their body adapts to burning fat as the predominant fuel. This is commonly referred to as the keto flu.

It’s not dangerous, but it can be unpleasant. While some people will only feel slightly tired for the first few days, most people experience headaches, fatigue, and irritability as a result of low blood sugar. However, these symptoms are only temporary. Once your body adapts to ketosis and becomes efficient at burning stored fat, you’ll likely have more energy and feel better than before.

Common adverse effects include:

Constipation (33%)
Unpleasant breath (30%)
Muscle cramps (28%)
Fatigue and dizziness
Headaches
Difficulty concentrating (“brain fog”)
Irritability
Sugar cravings
Diarrhea
Skin Rashes (if high in dairy)

Increased blood triglycerides
Dehydration (as carbohydrates carry water)
Kidney problems

Who is the Ketogenic Diet not Suitable for?

It is important to remember that there is no ‘one-size-fits-all’ diet. If you are diabetic, have a history of obesity, high blood pressure, high cholesterol, or are pregnant or breastfeeding it is imperative that you consult with your health care provider before beginning a ketogenic diet, and then, do so under the supervision of a registered dietitian. Individuals following other restrictive diets, such as vegetarian, vegan, or dairy-free should also seek professional advice to formulate a diet that meets all of their nutritional needs.

Take Home Message

While inter-individual variability exists, it is evident that a well-formulated ketogenic diet can be a successful weight loss strategy, that may offer other health benefits as well.

References

[1] http://htuneup.com/diseases/d_overweight.pdf

[2] https://www.cdc.gov/chronicdisease/resources/infographic/chronic-diseases.htm

[3] https://www.ncbi.nlm.nih.gov/pubmed/26768850

[4] https://www.ncbi.nlm.nih.gov/pubmed/15148063

[5] https://www.ncbi.nlm.nih.gov/pubmed/23651522

[6] https://www.ncbi.nlm.nih.gov/pubmed/15533250

[7] https://onlinelibrary.wiley.com/doi/abs/10.1111/obr.12230

[8] https://www.ncbi.nlm.nih.gov/pubmed/23632752

[9] http://www.cfp.ca/content/cfp/64/12/906.full.pdf

[10] https://www.ncbi.nlm.nih.gov/pubmed/18175736

[11] https://www.ncbi.nlm.nih.gov/pubmed/25698989

[12] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663603/

[13] https://www.ncbi.nlm.nih.gov/pubmed/17663761

[14] https://www.ncbi.nlm.nih.gov/pubmed/12097663

[15] https://academic.oup.com/nutritionreviews/article-abstract/77/3/161/5241079

[16] https://www.ncbi.nlm.nih.gov/pubmed/15767618

[17] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2633336/

[18] https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-4-5

[19] https://www.ncbi.nlm.nih.gov/pubmed/17448569

[20] https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-2-35

[21] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2367001/

[22] https://www.ahajournals.org/doi/pdf/10.1161/CIR.0000000000000510

[23] https://academic.oup.com/ajcn/article/104/5/1209/4564387

[24] https://www.karger.com/Article/Abstract/75591

25] https://www.tandfonline.com/doi/abs/10.1080/10408398.2014.

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