The Ketogenic Diet: A Detailed Beginner’s Guide to
Keto
The
ketogenic diet involves consuming a very low amount of carbohydrates and
replacing them with fat to help your body burn fat for energy. Health benefits
can include weight loss and lowering your risk for certain diseases.
The
ketogenic diet (or keto diet, for short) is a low carb, high fat diet that
offers many health benefits.
In
fact, many studies show that this type of diet can help you lose weight and
improve your health.
Ketogenic
diets may even have benefits against diabetes, cancer, epilepsy, and
Alzheimer’s disease.
Keto basics
The
ketogenic diet is a very low carb, high fat diet that shares many similarities
with the Atkins and low
carb diets.
It
involves drastically reducing carbohydrate intake and replacing it with fat.
This reduction in carbs puts your body into a metabolic state called ketosis.
When
this happens, your body becomes incredibly efficient at burning
fat for energy. It also turns fat into ketones in
the liver, which can supply energy for the brain
Ketogenic
diets can cause significant reductions in blood sugar and insulin levels. This,
along with the increased ketones, has some health benefits.
SUMMARY
The keto diet is a
low carb, high fat diet. It lowers blood sugar and insulin levels and shifts
the body’s metabolism away from carbs and toward fat and ketones.
Despite continuous advances in the medical world, obesity continues to
remain a major worldwide health hazard with adult mortality as high as 2.8
million per year. The majority of chronic diseases like diabetes, hypertension,
and heart disease are largely related to obesity which is usually a product of
an unhealthy lifestyle and poor dietary habits.
Appropriately tailored diet regimens for weight reduction can help
manage the obesity epidemic to some extent. One diet regimen that has proven to
be very effective for rapid weight loss is a very-low-carbohydrate and high-fat
ketogenic diet. This activity reviews the evaluation and considerations for the
ketogenic diet and discusses the role of the interprofessional team in
educating patients on the risks and benefits of this diet.
Objectives:
- Describe
the significance of obesity as a health hazard worldwide.
- Identify
the major diseases associated with obesity.
- Outline
the use of the ketogenic diet in treating obesity.
- Review
the evaluation and considerations for the ketogenic diet and outline the
role of the interprofessional team in educating patients on the risks and
benefits of this diet.
Function
A ketogenic diet primarily consists of high fats, moderate proteins, and
very low carbohydrates. The dietary macronutrients are divided into
approximately 55% to 60% fat, 30% to 35% protein, and 5% to 10% carbohydrates.
Specifically, in a 2000 kcal per day diet, carbohydrates amount up to 20 to 50
g per day.
History and Origin
Russel Wilder first used the ketogenic diet to treat epilepsy in
1921. He also coined the term "ketogenic diet." For almost a decade, the
ketogenic diet enjoyed a place in the medical world as a therapeutic diet for
pediatric epilepsy and was widely used until its popularity ceased with the
introduction of antiepileptic agents. The resurgence of the ketogenic diet as a
rapid weight loss formula is a relatively new concept the has shown to be quite
effective, at least in the short run.
Physiology and Biochemistry
Basically, carbohydrates are the primary source of energy production in
body tissues. When the body is deprived of carbohydrates due to reducing intake
to less than 50g per day, insulin secretion is significantly reduced and the
body enters a catabolic state. Glycogen stores deplete, forcing the body to go
through certain metabolic changes. Two metabolic processes come into action
when there is low carbohydrate availability in body tissues: gluconeogenesis and ketogenesis.
Gluconeogenesis is the endogenous
production of glucose in the body, especially in the liver primarily from
lactic acid, glycerol, and the amino acids alanine and glutamine. When glucose
availability drops further, the endogenous production of glucose is not
able to keep up with the needs of the body and ketogenesisbegins in order to provide an alternate source of energy
in the form of ketone bodies. Ketone bodies replace glucose as a primary source
of energy. During ketogenesis due to
low blood glucose feedback, the stimulus for insulin secretion is also low,
which sharply reduces the stimulus for fat and glucose storage. Other hormonal
changes may contribute to the increased breakdown of fats that result in fatty
acids.
Fatty acids are metabolized to acetoacetate which is
later converted to beta-hydroxybutyrate
and acetone. These are the basic
ketone bodies that accumulate in the body as a ketogenic diet is sustained.
This metabolic state is referred to as "nutritional ketosis." As long
as the body is deprived of carbohydrates, the metabolism remains in the ketotic
state. The nutritional ketosis state is considered quite safe, as ketone bodies
are produced in small concentrations without any alterations in blood pH. It
greatly differs from ketoacidosis, a life-threatening condition where ketone
bodies are produced in extremely larger concentrations, altering blood ph to an
acidotic state.
Ketone bodies synthesized in the body can be easily utilized for energy
production by the heart, muscle tissue, and kidneys. Ketone bodies also can
cross the blood-brain barrier to provide an alternative source of energy to the
brain. RBCs and the liver do not utilize ketones due to lack of mitochondria
and enzyme diaphorase respectively. Ketone body production depends on several
factors such as resting basal metabolic rate (BMR), body mass index (BMI), and
body fat percentage. Ketone bodies produce more adenosine triphosphate in
comparison to glucose, sometimes aptly called a "super fuel." One
hundred grams of acetoacetate generates 9400 grams of ATP, and 100 g of
beta-hydroxybutyrate yields 10,500 grams of ATP; whereas, 100 grams of glucose
produces only 8,700 grams of ATP. This allows the body to maintain efficient
fuel production even during a caloric deficit. Ketone bodies also decrease free
radical damage and enhance antioxidant capacity.
Issues
of Concern
Adverse Effects
The short-term effects (up to 2 years) of the ketogenic diet are well
reported and established. However, the long-term health implications are not
well known due to limited literature.
The most common and relatively minor short-term side effects of the
ketogenic diet include a collection of symptoms like nausea, vomiting,
headache, fatigue, dizziness, insomnia, difficulty in exercise tolerance, and
constipation, sometimes referred to as keto flu. These symptoms resolve in a
few days to few weeks.
Ensuring adequate fluid and electrolyte intake can help counter some of
these symptoms. Long-term adverse effects include hepatic steatosis,
hypoproteinemia, kidney stones, and vitamin and mineral deficiencies.
Cautions and Contraindications
People suffering from diabetes and taking insulin or oral
hypoglycemic agents suffer severe hypoglycemia if the medications are not
appropriately adjusted before initiating this diet. The ketogenic diet is
contraindicated in patients with pancreatitis, liver failure, disorders of fat
metabolism, primary carnitine deficiency, carnitinepalmitoyltransferase
deficiency, carnitinetranslocase deficiency, porphyrias, or pyruvate kinase
deficiency. People on a ketogenic diet rarely can have a false positive
breath alcohol test. Due to ketonemia, acetone in the body can sometimes be
reduced to isopropanol by hepatic alcohol dehydrogenase which can give a false
positive alcohol breath test result.
Clinical
Significance
The popular belief that high-fat diets cause obesity and several
other diseases such as coronary heart disease, diabetes, and cancer has not
been observed in recent epidemiological studies. Studies carried out in animals
that were fed high-fat diets did not show a specific causal relationship
between dietary fat and obesity. On the contrary, very-low-carbohydrate and
high-fat diets such as the ketogenic diet have shown to beneficial to weight
loss.
Evidence Behind The Ketogenic Diet
In relation to overall caloric intake, carbohydrates comprise
around 55% of the typical American diet, ranging from 200 to 350 g/day. The
vast potential of refined carbohydrates to cause harmful effects were
relatively neglected until recently. A greater intake of sugar-laden food is
associated with a 44% increased prevalence of metabolic syndrome and obesity
and a 26% increase in the risk of developing diabetes mellitus. In a 2012
study of all cardiometabolic deaths (heart disease, stroke, and type 2
diabetes) in the United States, an estimated 45.4% were associated with suboptimal
intakes of 10 dietary factors. The largest estimated mortality was associated
with high sodium intake (9.5%), followed by low intake of nuts and seeds
(8.5%), high intake of processed meats (8.2%), low intake of omega-3 fats
(7.8%), low intake of vegetables 7.6%), low intake of fruits (7.5%), and high
intake of artificially sweetened beverages (7.4%). The lowest estimated
mortality was associated with low polyunsaturated fats (2.3%) and
unprocessed red meats (0.4%). In addition to this direct harm, excess consumption
of low-quality carbohydrates may displace and leave no room in the diet for
healthier foods like nuts, unprocessed grains, fruits, and vegetables.
A recent systemic review and meta-analysis of randomized
controlled trials comparing the long-term effects (greater than 1 year) of
dietary interventions on weight loss showed no sound evidence for recommending
low-fat diets. In fact, low-carbohydrate diets led to significantly greater
weight loss compared to low-fat interventions. It was observed that a carbohydrate-restricted
diet is better than a low-fat diet for retaining an individual’s BMR. In other
words, the quality of calories consumed may affect the number of calories
burned. BMR dropped by more than 400 kcal/day on a low-fat diet when compared to
a very low-carb diet.
A well-formulated ketogenic diet, besides limiting carbohydrates,
also limits protein intake moderately to less than 1g/lb body weight, unless
individuals are performing heavy exercise involving weight training when the
protein intake can be increased to 1.5g/lb body weight. This is to prevent the
endogenous production of glucose in the body via gluconeogenesis. However, it
does not restrict fat or overall daily calories. People on a ketogenic diet
initially experience rapid weight loss up to 10 lbs in 2 weeks or less. This
diet has a diuretic effect, and some early weight loss is due to water weight
loss followed by a fat loss. Interestingly with this diet plan, lean body
muscle is largely spared. As a nutritional ketosis state sustains, hunger pangs
subside, and an overall reduction in caloric intake helps to further weight
loss.
Other
Issues
Long-term compliance is low and can be a big issue with a
ketogenic diet, but this is the case with any lifestyle change. Even
though the ketogenic diet is significantly superior in the induction of weight
loss in otherwise healthy patients with obesity and the induced
weight loss is rapid, intense, and sustained until at least 2 years, the
understanding of the clinical impacts, safety, tolerability, efficacy, duration
of treatment, and prognosis after discontinuation of the diet is challenging
and requires further studies to understand the disease-specific mechanisms.
A ketogenic diet may be followed for a minimum of 2 to 3 weeks up
to 6 to 12 months. Close monitoring of renal functions while on a ketogenic
diet is imperative, and the transition from a ketogenic diet to a standard diet
should be gradual and well-controlled.
Enhancing
Healthcare Team Outcomes
To counter the obesity epidemic, some healthcare workers do
recommend the ketogenic diet. However, the primary care provider, nurse
practitioner, dietitian, and internist need to be aware of a few facts.
Overweight individuals with metabolic syndrome, insulin
resistance, and type 2 diabetes are likely to see improvements in the clinical
markers of disease risk with a well-formulated very-low-carbohydrate diet.
Glucose control improves due to less glucose introduction and improved insulin
sensitivity. In addition to reducing weight, especially truncal obesity and
insulin resistance, low-carb diets also may help improve blood
pressure, blood glucose regulation, triglycerides, and HDL cholesterol levels.
However, LDL cholesterol may increase on this diet.
Also, in various studies, the ketogenic diet has shown promising
results in a variety of neurological disorders, like epilepsy, dementia, ALS,
traumatic brain injury, acne, cancers, and metabolic disorders.
Due to the complexity of the mechanism and lack of long-term
studies, a general recommendation of the ketogenic diet for prevention of type
2 diabetes mellitus or cardiovascular disease may seem premature but is,
however, not farfetched for primary weight loss.
While in the short term the ketogenic diet may help one lose
weight, this is not sustained over the long run. In addition, countless studies
show that the diet is associated with many complications that often lead to
emergency room visits and admissions for dehydration, electrolyte disturbances,
and hypoglycaemia
0 Comments