Keto And Metabolism: Friend Or Foe?

The ketogenic diet, or keto, is a low-carbohydrate, high-fat eating plan that has been used for centuries to treat specific medical conditions. In recent years, it has gained popularity as a weight-loss strategy. Keto involves drastically reducing carbohydrate intake and replacing carbs with fat. This is a significant change for the body's metabolism and can lead to some serious side effects. While keto can help with weight loss, it may not be sustainable or healthy in the long term. Some studies suggest that keto can lead to poor metabolism, weight gain, and increased risk of heart disease and cancer. However, there is also research indicating potential health benefits of keto, such as reduced risk of metabolic syndrome, cardiovascular disease, and diabetes.

Keto may increase 'bad' cholesterol

Keto May Increase Bad Cholesterol

The keto diet is a popular, high-fat, moderate-protein, and very low-carbohydrate diet. It involves restricting your total carbohydrate intake to 20–50 grams per day, which forces your body to shift from using glucose as its main source of energy to using ketone bodies, a type of chemical formed from the breakdown of fat.

The worry is that following a very high-fat diet will create a subsequent spike in cholesterol levels, which could, in turn, raise your risk for heart disease. This worry is valid, as the keto diet may not have as detrimental an effect on your cholesterol as previously thought.

Research shows that the impact the keto diet has on lipids is modest, with most studies showing keto produces modest reductions in triglycerides, modest changes in heart-protective high-density lipoprotein (HDL, or "good"), and minimal changes in low-density lipoprotein (LDL, or "bad") levels. Some studies, however, show an increase in LDL on low- or very low-carb diets.

Whether these numbers go up or down largely depends on the quality of your keto diet. One problem is that there’s not a single ketogenic diet, and there are different ways to follow it. Some people are careful about the types of fats they eat, while others are not.

In human studies on people of normal weight and with obesity, keto diets are generally associated with a reduction in total cholesterol, an increase in HDL, a decrease in triglycerides, and reductions in LDL. At the same time, other research shows something different: a rise in LDL or no swing either way. In trials where LDL decreased, people ate a low-carb diet high in healthy unsaturated fat and limited in unhealthy saturated fat.

One past study compared a low-calorie and a very low-carb, high-fat diet (keto diet) in more than 360 overweight and obese participants. After about a year, those in the keto group saw their total cholesterol, triglycerides, and LDL decrease, while HDL rose.

The bottom line is that keto alone may not contribute to the cholesterol spike that some people report when starting the diet. But if you start eating more saturated fat because you’re on keto, then your LDL will likely rise. An increase in saturated fat intake has been shown over and over again to increase LDL.

Keto may harm people with a genetic mutation that affects LDL regulation. If these individuals follow a keto diet, their LDL levels can skyrocket. This result doesn’t happen often enough to skew overall results in population studies, but what matters most is the effect the diet has on your individual health.

If you have high cholesterol levels and are interested in trying the keto diet, it’s important to ask a healthcare professional whether the diet is suitable for you, based on your particular cholesterol levels and overall health.

Keto can cause nutrient deficiencies

The keto diet is a popular way to lose weight by restricting carbohydrates and replacing them with large amounts of healthy fats that your body burns for energy. However, because your intake of certain foods is limited, and in some cases may be eliminated completely, you may not get all the essential vitamins and minerals needed to maintain a healthy diet.

Common Nutrient Deficiencies on a Keto Diet

A high-fat/carb-restrictive diet like keto could lack the following vitamins and minerals necessary for a healthy diet:

• Vitamin B1
• Vitamin B6
• Vitamin B7
• Vitamin B12
• Calcium
• Iron
• Magnesium
• Phosphorus

These are all essential nutrients that your body needs to function properly. Our bodies don’t produce these vitamins and minerals, so we must get them daily from food or supplements.

B Vitamins

B vitamins are necessary for turning your food into energy.

Calcium, Magnesium, and Phosphorus

Calcium, magnesium, and phosphorus are crucial for strong bones.

Iron

Iron is needed to carry oxygen and help your body grow and develop properly.

Other Potential Deficiencies

In addition to the above, a keto diet may also be lower in fiber because whole grains are eliminated, so you may experience constipation.

A keto diet may also increase the risk of ketoacidosis for those with type-2 diabetes and raise bad cholesterol.

Preventing Nutrient Deficiencies on a Keto Diet

To prevent nutrient deficiencies on a keto diet, it is important to be aware of any nutrient deficiencies you may already have before starting the diet. You could become more deficient and cause additional health concerns when you eliminate certain foods from your diet.

Some keto-friendly food sources of essential nutrients include:

• High-quality meats like grass-fed beef, pastured pork, poultry, and eggs will give your body the necessary B vitamins, iron, and phosphorus.
• Dark, leafy greens, broccoli, and avocados are good vitamin B2, B6, B7, calcium, and magnesium sources.
• Full-fat yogurt is a good way to get vitamin B1, calcium, and phosphorus.
• Salmon, canned sardines, and some plant-based milks (e.g., almond and coconut) are good sources of calcium.

It is also recommended to speak with your doctor before starting a keto diet, especially if you have any health issues, concerns, or questions.

Keto can lead to osteoporosis

Keto diets have been associated with impaired bone health in several studies. While the diet has been linked to effective weight loss, it may also cause bone loss.

Human Studies

A systematic review of human studies found that keto diets are associated with an increased risk of bone mineral density (BMD) loss. The review found that keto diets alter vitamin D levels, lower growth factors, and cause a high "acid load" via the ketone bodies, all of which contribute to a higher risk of BMD loss.

Another study of 30 elite race walkers on a keto diet for three and a half weeks found a decrease in markers for bone metabolism and formation and an increase in markers of bone breakdown.

Animal Studies

Animal studies have also shown that keto diets can lead to low BMD and abnormal cortical and cancellous bone mass. Mice on a keto diet, for example, showed impaired microarchitecture of the trabecular bone of the femur, similar to that caused by ovariectomy.

Osteoporosis

While the studies do not definitively prove that keto diets cause osteoporosis, they suggest that the diets may lead to impaired bone health. The risk of osteoporosis is particularly relevant for people with obesity, who often use keto diets for weight loss.

Therefore, while keto diets may be effective for weight loss in the short term, they may also have negative consequences for bone health, which could increase the risk of osteoporosis.

Keto can cause kidney stones

The ketogenic diet is a low-carb, high-fat diet that is commonly used for weight loss. It involves keeping the intake of carbohydrates to a minimum, typically fewer than 50 grams per day. While this diet can lead to weight loss, it also carries certain health risks, including kidney stones.

The keto diet relies heavily on high-fat animal foods such as eggs, meat, and cheese, which can increase the risk of kidney stones. This is because a high intake of animal products can make the blood and urine more acidic, leading to increased excretion of calcium in the urine. Some studies also suggest that the keto diet reduces the amount of citrate in the urine, which is important because citrate can bind to calcium and prevent the formation of kidney stones.

The incidence of kidney stones among those on the keto diet ranges from 3% to 10%, compared to about one in several thousand in the general population. Uric acid stones are the most common type of kidney stones in people on the keto diet, followed by calcium-based stones.

The exact mechanism of kidney stone formation on the keto diet is not entirely clear, but it is likely related to hypocitraturia and acidosis, which are common in people consuming a high-protein and low-alkali diet. Acidosis contributes to significant reabsorption of citrate in the proximal tubule, further reducing its levels in the urine. The low urine pH associated with a low-alkali diet also promotes the formation of uric acid crystals, which can act as a nucleus for calcium-based kidney stones.

Dehydration is another important factor that contributes to kidney stone formation on the keto diet. Ketosis has been shown to interfere with the normal thirst mechanism, leading to reduced fluid intake and increased risk of dehydration.

To mitigate the risk of kidney stones, it is recommended to liberalize fluid intake and avoid the initial fasting phase when starting the keto diet. Screening for underlying metabolic disorders before initiating the diet can also help avoid substantial acidosis, which is a contributing factor to kidney stone formation.

Keto can cause constipation

The keto diet can cause constipation, which is often referred to as "keto constipation". This is due to several reasons:

Firstly, the keto diet is typically low in fiber. The diet involves drastically cutting back on carbs and increasing the consumption of fats and proteins. Carbohydrates like fruits and whole grains are common sources of fiber, so transitioning to a low-carb diet can lead to a reduction in fiber intake, causing digestive issues like constipation.

Secondly, some individuals on the keto diet may consume more dairy, which is allowed on the diet due to its high fat and protein content. However, dairy is a common cause of constipation because lactose, the sugar found in milk, can be difficult to digest and lead to bloating, gas, nausea, and constipation.

Thirdly, the keto diet may also lead to reduced water intake. With a lower consumption of fruits and vegetables, which have high water content, individuals on the keto diet may not realize they are becoming dehydrated. Dehydration and an imbalance of electrolytes are more prevalent on a keto diet because glycogen, the stored form of sugar, is stored with water in the muscles.

To treat and prevent constipation while on the keto diet, it is recommended to:

• Increase fiber intake by consuming more keto-friendly, high-fiber foods such as non-starchy vegetables, berries, avocados, and nuts.
• Drink plenty of water to stay hydrated.
• Exercise regularly, as physical activity can help regulate bowel movements.
• Retrain the bowel by reestablishing frequent bowel movements and drinking sufficient fluids.
• Cut back on dairy if it is causing digestive issues.

It is important to note that the keto diet can be extremely restrictive and challenging to maintain. It is recommended to consult a healthcare provider before starting any new diet, especially one as restrictive as the keto diet, to ensure it is safe and suitable for your individual needs.

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