The Truth About Low-Carb and Keto Diets: What You Need to Know

Low-carb and ketogenic diets have gained popularity for their weight loss benefits and potential to improve overall health. Both diets focus on reducing carbohydrate intake and increasing healthy fats and proteins, but the keto diet is more restrictive, leading the body into nutritional ketosis, where it burns fat for energy instead of glucose.

These dietary approaches offer several health benefits, such as improved blood sugar control, reduced body fat, and enhanced cardiovascular health. Studies, including randomized controlled trials, suggest they can be effective for managing conditions like type 2 diabetes and metabolic syndrome. However, potential risks, including nutrient deficiencies and concerns about high saturated fat intake, need consideration.

What Are Low-Carb and Keto Diets?

A low-carb diet restricts the intake of carbohydrates, primarily focusing on cutting carbs from foods like starchy vegetables, whole grains, and sweets. Instead, it emphasizes proteins, healthy fats, and low-carb vegetables. There are various forms of low-carb diets, ranging from moderate carb intake to more restrictive options like the ketogenic diet.

The keto diet, or ketogenic diet, is a type of very low carbohydrate, high-fat diet. By drastically reducing carb intake and replacing it with fat, the body enters a state of nutritional ketosis. In this state, the body breaks down fatty acids into ketone bodies, which become the primary source of energy instead of glucose.

How Do Low-Carb and Keto Diets Work?

The core principle behind both low-carb and keto diets is to lower the intake of carbs to shift the body’s energy source. When carbs are cut, the body begins to burn fat stored in tissues, leading to fat loss. This metabolic change can be particularly effective for people looking to lose weight quickly, especially those dealing with insulin resistance or metabolic syndrome.

In a typical ketogenic diet, the macronutrient breakdown consists of about 70-75% fat, 20-25% protein, and only 5-10% carbohydrates. This high-fat nature promotes the production of ketone bodies, which fuel the brain and body. For some, a low-calorie ketogenic diet may also be used to maintain a normal weight without experiencing constant hunger.

Benefits of Low-Carb and Keto Diets

One of the most well-known benefits of low-carb diets is their effectiveness in weight loss. Numerous randomized controlled trials and studies, including a systematic review and meta-analysis, have found that low carbohydrate diets lead to a significant reduction in body weight. By reducing carb intake, the body taps into stored fat for energy, leading to faster and more sustainable fat loss.

Keto diets may help reduce visceral fat, which is stored around internal organs, lowering the risk of chronic diseases. By promoting the use of fat as the primary energy source, these diets can aid individuals in achieving a leaner physique and more weight loss than traditional low-fat diets.

Improved Blood Sugar and Insulin Sensitivity

Another key benefit of low carbohydrate ketogenic diets is their ability to manage blood sugar levels. Reducing the intake of carbs can lead to lower blood sugar and improved insulin sensitivity, making these diets beneficial for those with type 2 diabetes or polycystic ovary syndrome (PCOS). By stabilizing blood sugar levels, these diets help reduce cravings and promote a feeling of fullness, which can further support weight loss.

Cardiovascular Health

Research shows that low-carb diets may improve several cardiovascular health markers, including a reduction in elevated triglycerides and an increase in high-density lipoprotein (HDL), often known as “good” cholesterol. A diet reduced in carbohydrates can lead to a decrease in other cardiometabolic risk factors, including blood pressure, body mass, and elevated triglycerides, contributing to better heart health.

However, it’s important to be mindful of the types of fats consumed. While high-fat diets that include fatty fish, avocados, and nuts are beneficial, excessive intake of saturated fats from processed foods and red meat may increase the risk of cardiovascular disease.

Appetite Control and Reduced Cravings

Low-carb and keto diets are also known for their ability to suppress hunger. The high protein intake and healthy fats associated with these diets can help individuals feel full and satisfied, reducing the likelihood of overeating. By maintaining a steady energy supply from healthy fats, the body doesn’t experience the typical spikes and crashes in blood sugar that often lead to cravings on high carb diets.

Potential Risks and Side Effects

Many people experience a phenomenon known as the keto flu when they first switch to a keto diet. Symptoms may include headaches, fatigue, nausea, and irritability as the body adjusts to a low carbohydrate ketogenic state. These symptoms are temporary but can be unpleasant, often deterring individuals from continuing the diet. Adequate hydration, electrolyte balance, and a gradual transition can help mitigate these effects.

Nutrient Deficiencies

Because low-carb and ketogenic diets limit several food groups, there is a risk of nutrient deficiencies, especially in vitamins and minerals that are abundant in whole grains, fruits, and starchy vegetables. These diets may lack fiber, vitamin C, and potassium, potentially leading to digestive issues like constipation. It’s essential to include low-carb, nutrient-dense foods like leafy greens, nuts, and fatty fish to avoid deficiencies.

Potential Impact on Cardiovascular Health

While some studies suggest that low-carb diets may improve cardiovascular health, others raise concerns about their high fat and saturated fat content, which could lead to an increased risk of cardiovascular disease if not carefully managed. Saturated fats, found in butter, cheese, and certain oils, should be consumed in moderation, as recommended by health organizations like the National Lipid Association Nutrition and Lifestyle Task Force.

Changes in Body Composition

Although low-carb and keto diets can lead to weight loss, they may also affect lean body mass. Rapid weight loss on these diets can sometimes result in muscle loss if protein intake is not sufficient. To preserve lean mass, it’s essential to consume an adequate amount of protein and include resistance training as part of a healthy lifestyle.

How Do Low-Carb and Keto Diets Affect Metabolism?

The shift to nutritional ketosis causes the body’s resting metabolic rate to rely more on fat than on glucose. While this can lead to fat loss, it’s important to note that the body’s ability to adapt may vary between individuals. Factors like insulin sensitivity, metabolic syndrome, and other cardiometabolic risk factors can influence how well a person responds to a low carbohydrate ketogenic diet.

Who Can Benefit Most from Low-Carb and Keto Diets?

One of the most significant health benefits of low-carb and ketogenic diets is their ability to improve blood sugar control. For those with type 2 diabetes, these diets can be a useful tool for managing glucose levels and reducing dependence on medication. The reduction in carb intake leads to lower glucose spikes, helping stabilize insulin sensitivity. Numerous randomized controlled trials have shown that a low carbohydrate diet can lead to a significant reduction in blood sugar levels, making it a potential strategy for diabetes management.

Obese Adults and Weight Management

Obese adults struggling with weight management may also find low-carb diets effective. These diets promote fat loss by encouraging the body to burn fat instead of relying on carbohydrates. Furthermore, ketogenic diets have been shown to lead to greater weight loss compared to low-fat diets, partly due to their ability to curb appetite and maintain muscle. By reducing body mass, these diets can help lower the risk of obesity-related conditions such as cardiovascular disease and metabolic syndrome. Diet myths often promote restrictive or misleading ideas about nutrition, leading people away from balanced, science-based approaches to healthy eating.

People with Metabolic Syndrome and Insulin Resistance

Metabolic disease, which often includes a combination of conditions like elevated triglycerides, high blood pressure, and insulin resistance, can be improved with low-carb and keto diets. Reducing carb intake helps address these cardiometabolic risk factors, leading to better cardiovascular health and a lower likelihood of developing type 2 diabetes. Studies have indicated that these diets can lead to improvements in resting metabolic rate and reduce visceral fat, which is closely linked to metabolic syndrome.

Potential Risks and Considerations

For those with pre-existing kidney disease, low-carb and ketogenic diets may pose some challenges. High protein intake, a feature of many low-carb diets, can stress the kidneys, particularly in those with reduced kidney function. It is essential for individuals with any degree of kidney disease to consult a healthcare provider before starting a low carbohydrate or keto diet. In such cases, careful monitoring of protein sources and overall intake is crucial.

Effects on Bone Health

Some review and meta-analysis studies have raised concerns about the potential effects of ketogenic diets on bone health. While these diets are effective for fat loss and weight management, they may lead to a decrease in bone density if not properly managed. Ensuring adequate vitamin D, calcium, and lean protein intake can help mitigate these risks, particularly for those who follow the diet for extended periods.

High Saturated Fat Intake and Heart Health

A typical keto diet is a high fat diet, and while it can lead to improved heart health markers, there are concerns regarding the intake of saturated fats. Consuming more saturated fat than recommended can potentially lead to an increased risk of cardiovascular disease. Saturated fats from foods like butter, cheese, and processed meats should be limited in favor of healthier fats from fatty fish, nuts, and olive oil to promote better cardiovascular health.

Keto Flu and Other Side Effects

As mentioned in Part 1, the keto flu is a common side effect experienced by those new to low carbohydrate ketogenic diets. It occurs as the body adapts to nutritional ketosis, where it shifts from using glucose to ketone bodies for energy. Symptoms can include headache, nausea, fatigue, and irritability. While the keto flu is temporary, staying hydrated and replenishing electrolytes can help alleviate these discomforts.

Digestive Issues and Constipation

Switching to a low carbohydrate ketogenic diet can sometimes lead to digestive issues, including constipation. This is often due to the reduced intake of whole grains and fiber-rich foods, which are essential for regular bowel movements. To maintain gut health, it’s important to consume leafy greens, nuts, and other low-carb, fiber-rich foods. Some individuals may also benefit from dietary supplements that include fiber.

How to Safely Follow a Low-Carb or Keto Diet

Following a low-carb or ketogenic diet can be sustainable and healthy when done correctly. Focus on including lean meats, fatty fish, leafy greens, nuts, and healthy oils like olive and avocado oil. Low-carb vegetables such as broccoli, cauliflower, spinach, and zucchini provide essential vitamins and minerals without significantly increasing carb intake. Starchy vegetables and whole grains should be limited or avoided, depending on the diet.

The Importance of Protein and Healthy Fats

Maintaining the right protein intake is crucial for preserving lean body mass, especially during weight loss. However, it’s important to balance protein consumption with healthy fats. Foods high in omega-3 fatty acids, such as fatty fish, avocados, and nuts, should be a regular part of your diet. These fats promote heart health and help maintain cognitive function.

Avoid more saturated fat sources, and choose healthier alternatives to ensure you are getting the potential health benefits without the risks associated with a high-fat diet.

Monitoring Health Markers

Regular monitoring of health markers, including blood pressure, cholesterol levels, and blood sugar, is vital for anyone on a low-carb or keto diet. These diets can significantly alter your body’s metabolism, so regular check-ups can help ensure you are not facing any adverse effects. Consulting with healthcare professionals who are knowledgeable about ketogenic diets can also help manage any cardiometabolic risk factors and improve health outcomes.

Debunking Myths About Low-Carb and Keto Diets

While they share some similarities, low-carb diets and keto diets are not identical. A keto diet is a more extreme version of a low-carb diet with a strict limit on carb intake to induce nutritional ketosis. Not all low-carb diets require reaching ketosis, and some allow a more flexible intake of carbs.

A common misconception is that all fats lead to weight gain and heart disease. However, it’s important to differentiate between types of fats. Healthy fats, such as those found in avocados, fatty fish, and nuts, provide essential nutrients and support overall cardiovascular health. Conversely, processed foods that contain trans fats and saturated fats can lead to increased risk of health issues if consumed excessively.

Conclusion

Low-carb and keto diets offer numerous potential health benefits, particularly for those looking to manage weight, blood sugar, and cardiometabolic risk factors. However, these benefits come with certain risks, such as nutrient deficiencies, digestive issues, and concerns about high saturated fat intake. Understanding how to implement these diets safely is crucial for reaping the benefits while minimizing the downsides.

By choosing balanced, low-carb options, focusing on healthy fats, and ensuring adequate protein intake, individuals can follow a low carbohydrate diet that supports long-term health. Consulting with healthcare providers and staying informed about dietary trends, such as intermittent fasting combined with low-carb eating, can also help tailor these approaches to meet individual needs.