Are you navigating the complex world of weight-loss strategies and diet plans? The ketogenic, or "keto," diet is a time-honored eating plan characterized by its low-carbohydrate and high-fat composition, initially employed centuries ago for specific medical conditions. In the 19th century, it was a common method to manage diabetes. By 1920, it was recognized as an effective treatment for epilepsy in children for whom medication proved ineffective. Today, the keto diet has gained considerable attention as a potential weight-loss strategy, fueled by the low-carb diet trend that began in the 1970s with the Atkins diet.
The Ketogenic Diet: How It Works
The main idea behind the ketogenic diet as a weight-loss method is that by depriving the body of glucose-the primary energy source for cells obtained from carbohydrate-rich foods-an alternative fuel source known as ketones is produced from stored fat. The brain, which cannot store glucose, requires a steady supply of about 120 grams of glucose daily. During periods of fasting or when carbohydrate intake is minimal, the body initially utilizes stored glucose from the liver and temporarily breaks down muscle to release glucose. If this continues for 3-4 days, and stored glucose is fully depleted, insulin levels decrease, prompting the body to use fat as its primary fuel. The liver then produces ketone bodies from fat, which serve as an alternative energy source in the absence of glucose, leading to a state known as ketosis. Mild ketosis naturally occurs in healthy individuals during fasting or strenuous exercise. Proponents of the ketogenic diet suggest that, when carefully followed, ketone levels should not reach harmful levels, as the brain will use ketones for fuel, and the body will produce enough insulin to prevent excessive ketone formation. The rate at which ketosis occurs and the accumulation of ketone bodies vary among individuals, depending on factors such as body fat percentage and resting metabolic rate.
Ketoacidosis: Understanding the Risks
Excessive ketone bodies can lead to ketoacidosis, a condition where dangerously high levels of acid accumulate in the blood. During ketoacidosis, the kidneys excrete ketone bodies along with body water in the urine, resulting in fluid-related weight loss. Ketoacidosis primarily affects individuals with type 1 diabetes due to their inability to produce insulin, which prevents ketone overproduction. However, rare cases have been reported in non-diabetic individuals following prolonged very-low-carbohydrate diets.
Macronutrient Ratios in the Ketogenic Diet
There is no universally accepted "standard" ketogenic diet with a specific macronutrient ratio. However, it typically involves reducing total carbohydrate intake to less than 50 grams per day, and in some cases, as low as 20 grams per day. Popular ketogenic resources often suggest a composition of 70-80% fat, 5-10% carbohydrate, and 10-20% protein from total daily calories. For a 2000-calorie diet, this translates to approximately 165 grams of fat, 40 grams of carbohydrate, and 75 grams of protein. The ketogenic diet maintains a moderate protein intake compared to other low-carb, high-protein diets, as excessive protein consumption can hinder ketosis.
Foods to Avoid and Emphasize
While various versions of ketogenic diets exist, all restrict carb-rich foods. Obvious examples include starches from refined and whole grains like breads, cereals, pasta, rice, and cookies, as well as potatoes, corn, and other starchy vegetables, and fruit juices. Less obvious restrictions include beans, legumes, and most fruits. Most ketogenic plans allow foods high in saturated fat, such as fatty cuts of meat, processed meats, lard, and butter, in addition to sources of unsaturated fats like nuts, seeds, avocados, plant oils, and oily fish. Emphasis is placed on consuming fats at each meal and snack to meet the high-fat requirement. Some dairy foods may be permitted, although those high in lactose sugar, such as cream, ice cream, and full-fat milk, are restricted. Small portions of certain fruits, like berries, may be allowed, while others are restricted unless factored into the designated carbohydrate restriction.
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"Net Carbs" and "Impact Carbs": A Marketing Strategy
The terms "net carbs" and "impact carbs" are often encountered in ketogenic and diabetic diets. These unregulated, interchangeable terms are used by food manufacturers as a marketing strategy to suggest that a product contains fewer "usable" carbohydrates than listed. Net carbs or impact carbs refer to the amount of carbohydrate directly absorbed and contributing calories, calculated by subtracting indigestible carbohydrates from the total carbohydrate amount. Indigestible carbohydrates include insoluble fibers from whole grains, fruits, and vegetables, as well as sugar alcohols like mannitol, sorbitol, and xylitol, commonly found in sugar-free diabetic food products. However, these calculations are not precise, as the effect of sugar alcohols on absorption and blood sugar can vary. Despite the net carb amount, the total calorie level remains unchanged, which is an important factor in weight loss.
Short-Term Metabolic Changes and Potential Benefits
Ketogenic diet programs are typically followed until the desired amount of weight is lost. Studies have shown that the ketogenic diet can produce beneficial metabolic changes in the short term. In addition to weight loss, health parameters associated with excess weight, such as insulin resistance, high blood pressure, and elevated cholesterol and triglycerides, have shown improvement. There is also growing interest in using low-carbohydrate diets, including the ketogenic diet, for type 2 diabetes.
Studies on Ketogenic Diets for Weight Loss
Research findings have been limited to studies specifically examining the ketogenic diet, characterized by approximately 70-80% fat, 10-20% protein, and 5-10% carbohydrate. Diets termed "low carbohydrate" may not adhere to these specific ratios, allowing for higher amounts of protein or carbohydrate. Therefore, only diets that explicitly used the terms "ketogenic" or "keto," or followed the specified macronutrient ratios, were included in the studies below. Furthermore, while extensive research exists on the use of the ketogenic diet for other medical conditions, only studies that examined ketogenic diets specifically for obesity or overweight were included.
Meta-Analysis of Randomized Controlled Trials
A meta-analysis of 13 randomized controlled trials, which followed overweight and obese participants for 1-2 years on either low-fat diets or very-low-carbohydrate ketogenic diets, revealed that the ketogenic diet led to a small but significantly greater reduction in weight, triglycerides, and blood pressure, and a greater increase in HDL and LDL cholesterol compared to the low-fat diet at one year.
Systematic Review of Short-Term Intervention Trials
A systematic review of 26 short-term intervention trials (ranging from 4-12 weeks) evaluated the appetites of overweight and obese individuals on either a very low calorie (~800 calories daily) or ketogenic diet (no calorie restriction but ≤50 gm carbohydrate daily) using a standardized and validated appetite scale. The participants reported less hunger and a reduced desire to eat compared to baseline measures, despite losing a significant amount of weight on both diets. The authors suggested further studies exploring a threshold of ketone levels needed to suppress appetite, which could allow for the inclusion of healthful higher carbohydrate foods like whole grains, legumes, and fruit.
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Study on Obese Adults on a Ketogenic Very Low-Calorie Diet
A study of 39 obese adults placed on a ketogenic very low-calorie diet for 8 weeks found a mean loss of 13% of their starting weight and significant reductions in fat mass, insulin levels, blood pressure, and waist and hip circumferences. Their levels of ghrelin, a hunger hormone, did not increase while they were in ketosis, which contributed to a decreased appetite. However, during the 2-week period when they came off the diet, ghrelin levels and urges to eat significantly increased.
Study on Obese Adults on a Two-Phase Diet Regimen
A study of 89 obese adults who were placed on a two-phase diet regimen (6 months of a very-low-carbohydrate ketogenic diet and 6 months of a reintroduction phase on a normal calorie Mediterranean diet) showed a significant mean 10% weight loss with no weight regain at one year. Eighty-eight percent of the participants were compliant with the entire regimen.
Potential Risks and Side Effects
Maintaining a very high-fat diet may be challenging in the long term. Some potential negative side effects of a long-term ketogenic diet include an increased risk of kidney stones and osteoporosis, as well as elevated blood levels of uric acid, a risk factor for gout. Nutrient deficiencies may also arise if a variety of recommended foods on the ketogenic diet are not included. It is important to focus on including a daily variety of the allowed meats, fish, vegetables, fruits, nuts, and seeds to ensure adequate intakes of fiber, B vitamins, and minerals (iron, magnesium, zinc)-nutrients typically found in foods like whole grains that are restricted from the diet. Furthermore, questions remain regarding the diet’s health benefits for higher-risk individuals with multiple health conditions and the elderly, as well as the long-term impact on health from consuming different types of fats (saturated vs. unsaturated).
Limitations of Available Research
Available research on the ketogenic diet for weight loss is still limited. Most studies have had a small number of participants, were short-term (12 weeks or less), and did not include control groups. While the ketogenic diet has been shown to provide short-term benefits in some people, including weight loss and improvements in total cholesterol, blood sugar, and blood pressure, these effects are not significantly different from those of conventional weight loss diets after one year. Eliminating several food groups and the potential for unpleasant symptoms may make compliance difficult. Additionally, an emphasis on foods high in saturated fat counters recommendations from dietary guidelines and may have adverse effects on blood LDL cholesterol.
Recommendations and Conclusion
A ketogenic diet may be an option for some individuals who have struggled to lose weight with other methods. The exact ratio of fat, carbohydrate, and protein needed to achieve health benefits will vary among individuals due to their genetic makeup and body composition. Therefore, it is recommended to consult with a physician and a dietitian to closely monitor any biochemical changes after starting the regimen and to create a meal plan tailored to one’s existing health conditions to prevent nutritional deficiencies or other health complications. A modified carbohydrate diet following the Healthy Eating Plate model may produce adequate health benefits and weight reduction in the general population.
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Exogenous Ketones: An Alternative Approach
Exogenous ketones are supplements designed to mimic ketosis and raise blood ketone levels without requiring dietary changes. While the keto diet encourages ketosis, where the body burns fat instead of carbohydrates for energy, it can be difficult to follow consistently.
How Exogenous Ketones Work
If you follow a standard high-carb diet, your body’s cells typically rely on glucose for fuel. Glucose comes from the carbs in your diet, including sugars and starchy foods like bread, pasta, and some vegetables. If you restrict those foods, as with a ketogenic diet, you force your body to look for alternative fuel sources.Your body then turns to fat for fuel, which produces ketone bodies when broken down in excess. This shift in metabolism puts your body in a state of ketosis. The two main ketone bodies produced during ketosis are acetoacetate and beta-hydroxybutyrate, with acetone being a third, less abundant, ketone body. These ketone bodies replace glucose as fuel and provide your brain, heart, and muscles with energy.
Types of Exogenous Ketone Supplements
Ketones found in supplements are exogenous ketones. These supplements contain only the beta-hydroxybutyrate ketone because the other primary ketone body, acetoacetate, is not chemically stable as a supplement. There are two main forms of ketone supplements:
- Ketone salts: Ketones bound to a salt, typically sodium, potassium, calcium, or magnesium.
- Ketone esters: Ketones linked to another compound called an ester and packaged in liquid form.
Both forms of ketone supplements have been shown to increase blood ketone levels, mimicking the state of ketosis achieved through a ketogenic diet.
Potential Benefits of Exogenous Ketones
- Appetite Suppression: Some studies have shown that ketone supplements can decrease appetite, potentially aiding in weight loss by reducing food intake.
- Transitioning into Ketosis: Ketone supplements can help individuals transition into ketosis more quickly and reduce the unpleasant effects associated with the transition from a standard, higher-carb diet to a ketogenic one (the "keto flu").
- Athletic Performance: Some authors state that exogenous ketones appear to have an effect on the brain, heart, and skeletal muscle, which may have benefits to athletes. However, they concluded that the current evidence exogenous ketones are not a tool to improve athletic performance.
Potential Risks and Side Effects of Exogenous Ketones
- Gastrointestinal Issues: Reported side effects are more common with ketone salts than ketone esters and include nausea, diarrhea, and stomach discomfort.
- Electrolyte Imbalances: Taking ketone salts increases the risk of electrolyte imbalances due to the added minerals.
- Inhibition of Fat Breakdown: Taking ketone supplements may prevent body fat from being used as fuel, at least in the short term.
- Calorie Content: Ketones contain about four calories per gram, which can add up if multiple servings are consumed daily to maintain ketosis.
Regulatory Concerns
The Food and Drug Administration (FDA) does not regulate the exogenous ketone supplement market, meaning that these supplements are not tested or evaluated for safety, purity, or effectiveness by regulatory agencies.
Real Ketones and D-BHB Technology
Real Ketones is a weight loss supplement based on the science of exogenous ketones, specifically focusing on D-BHB ketone technology. This technology aims to improve energy, mental health and wellness, and reduce the risk of life-threatening illnesses such as diabetes and heart disease.
Clinical Study on D-BHB
A placebo-controlled, double-blind, IRB-approved clinical study was conducted to evaluate the effects of Real Ketones D-BHB on weight loss. The study found that participants taking D-BHB lost 2.5 times more fat than the control group and experienced improvements in total cholesterol and LDL cholesterol.
Key Findings from the D-BHB Weight Loss Study
- Participants lost 2.5 times more fat compared to the control group.
- Total cholesterol and LDL cholesterol levels were lowered.
- There were no serious adverse effects from taking ketone supplements.
How to Incorporate Real Ketones into Your Weight Loss Plan
- Set Realistic Goals: Remember that healthy weight loss takes time, and focus on fat loss rather than just weight loss.
- Monitor Your Progress: Keep track of your weight loss and fat loss results in a journal, smartphone, or spreadsheet.
- Consult with a Healthcare Professional: As with any weight loss plan, consult with your primary care physician before starting Real Ketones or making significant dietary changes.
The Broader Implications of Ketogenic Diets and Exogenous Ketones on Mental Health
Recent research has begun to explore the potential of ketogenic diets and exogenous ketones in managing serious mental illnesses such as schizophrenia and bipolar disorder. Standard treatments for these conditions often involve antipsychotic medications, which can have metabolic side effects like weight gain and insulin resistance.
Pilot Study on Ketogenic Diet and Mental Illness
A pilot study conducted by Stanford Medicine researchers found that a ketogenic diet not only restored metabolic health in patients with schizophrenia or bipolar disorder taking antipsychotic medications but also improved their psychiatric conditions. The participants followed a diet with approximately 10% of calories from carbohydrates, 30% from protein, and 60% from fat, emphasizing whole, non-processed foods.
Key Findings of the Pilot Study
- Metabolic Improvements: Significant improvements were seen in obesity, metabolic syndrome, and insulin resistance, even while patients continued taking antipsychotic drugs.
- Psychiatric Benefits: Participants showed a 31% improvement on a clinical global impressions scale, with three-quarters experiencing clinically meaningful improvement.
- Improved Quality of Life: Participants reported improvements in energy, sleep, mood, and overall quality of life.
Potential Mechanisms
The researchers suggest that the benefits of the ketogenic diet on mental health may be due to multiple mechanisms, including improved metabolic health and reduced excitability of neurons in the brain. The main purpose of this pilot trial was to detect signals that will guide the design of larger, more robust studies.
Implications for Treatment
These findings suggest that metabolic interventions like the ketogenic diet could be a valuable addition to the treatment of mental illnesses, addressing both the psychiatric and metabolic aspects of these conditions.
The Impact of Exogenous Ketone Salts on Hypocaloric Ketogenic Diets
A study examined the effects of exogenous ketone salts (KS) on overweight and obese adults following a hypocaloric ketogenic diet (KD). The study aimed to determine if KS supplementation could protect against muscle loss during caloric restriction.
Study Design and Methods
- Participants: Overweight and obese adults were provided a precisely defined hypocaloric KD (~75% of energy expenditure) for 6 weeks.
- Intervention: Participants were randomly assigned to receive ~24 g/day of a racemic BHB-salt (KD + KS) or placebo (KD + PL). A matched comparison group was separately assigned to an isoenergetic/isonitrogenous low-fat diet (LFD).
- Measurements: Body mass, whole body fat and lean mass, mid-thigh muscle cross-sectional area, and both visceral and subcutaneous adipose tissues were measured.
Results
The KD induced nutritional ketosis throughout the study, with higher fasting BHB concentrations observed in KD + KS than KD + PL for the first 2 weeks. There were decreases in body mass, whole body fat and lean mass, mid-thigh muscle cross-sectional area, and both visceral and subcutaneous adipose tissues. However, there were no group differences between the two KDs or with the LFD.
Conclusion
Energy-matched hypocaloric ketogenic diets favorably affected body composition but were not further impacted by administration of an exogenous BHB-salt that augmented ketosis.
Key Considerations for Implementing a Ketogenic Diet
- Consult with a Healthcare Professional: Before starting a ketogenic diet, it is essential to consult with a healthcare provider or registered dietitian to ensure it is appropriate for your individual health needs and to monitor for any potential side effects.
- Focus on Nutrient-Dense Foods: When following a ketogenic diet, prioritize whole, nutrient-dense foods, including non-starchy vegetables, healthy fats, and high-quality protein sources.
- Monitor Electrolyte Levels: Ketogenic diets can lead to electrolyte imbalances, so it is important to monitor and replenish electrolytes as needed.
- Stay Hydrated: Drink plenty of water to help prevent dehydration, which can be a common side effect of ketogenic diets.
- Be Mindful of Saturated Fat Intake: While ketogenic diets are high in fat, it is important to be mindful of saturated fat intake and prioritize healthy fats, such as monounsaturated and polyunsaturated fats.
- Consider Individual Needs: The specific macronutrient ratios and food choices for a ketogenic diet may need to be tailored to individual needs and preferences.