While there are many popular diets, the low-carb diet has to be one of the most popular nutritional approaches.
The diet itself is extremely uncomplicated and, as the name suggests, it simply involves restricting carbohydrate intake.
This article will unpack the low-carb diet, explain what’s involved, and review scientific articles to determine its effectiveness.
What Is The Low-Carb Diet?
Carbohydrates are sugars that the body uses as energy. They can be found in many commonly consumed foods such as bread, pasta, sugary snacks, and starchy vegetables.
The low-carb diet significantly restricts the number of carbohydrates consumed per day and instead focuses on consuming more protein and fat.
As with most diets, the most common reason the low-carb diet is used is to cause weight loss. It is also a popular diet for diabetics as it appears to help regulate blood sugar levels.
While each plan has its own unique approach to low-carb dieting, ultimately, the goal with all low-carb diets is the same. Reduce calorie intake by consuming fewer carbs.
There have been a number of scientific studies conducted on low-carb diets. The majority of the research agrees that low-carb diets can be beneficial for weight loss and health (1).
How Does It Work?
While carbs don’t directly impact weight loss, carbohydrates do tend to make up the bulk of our diets. Therefore, the majority of our calorie intake comes from carbohydrates.
By substantially reducing the number of carbs consumed per day, our calorie intake also reduces. This is significant when we understand that calories influence weight loss.
Reducing calorie intake and placing the body in a calorie deficit forces the body to find an alternative energy source.
As a consequence, fat stores are broken down to fulfill energy requirements. Providing this deficit is maintained over a prolonged period, significant weight loss will occur.
What Foods Can Be Eaten?
With carbohydrates restricted, the majority of calories will come from fat and protein sources.
Having a high protein intake during weight loss is recommended. It has been found to be beneficial for weight loss and can reduce hunger and maintain muscle mass (2).
Protein Food Examples:
Fat Food Examples:
- Nuts and Seeds
In addition to fat and protein, it’s imperative that plenty of low-carb fruits and vegetables are consumed. These provide an abundance of nutrients that are key for health and function.
What Foods Should Be Avoided?
Foods that are high in carbohydrates should be avoided. There are two types of carbohydrates – simple and complex.
Simple carbs tend to be nutrient-sparse and immediately provide the body with energy. Complex carbs are typically nutrient-dense and cause energy to be released more gradually.
Simple Carb Examples:
- Baked Goods
- Refined Sugar Products
- White Bread and Pasta
Complex Carb Examples:
- Wholegrain Bread and Pasta
Health Benefits Of The Low-Carb Diet
In this section, we will review the scientific research on the low-carb diet and determine the potential health benefits.
1. Weight Loss and Maintenance
What the Science Says
As reflected earlier, the low-carb diet has been found to be an effective weight-loss method.
The recommended daily intake for carbohydrates is 45-60% of our daily caloric intake. That is the equivalent of 200-300 grams of carbohydrates per day (3).
There are four calories per gram of carbohydrates. By following this recommendation we would consume 800-1200 calories from carbohydrates per day.
However, by cutting carbohydrate intake down to 100 grams or less, total calories consumed will fall to a maximum of 400.
This will make it significantly easier to create the calorie deficit needed for weight loss.
Research has concluded that the low-carb causes greater reductions in body weight than other diets, such as the low-fat diet (4).
Furthermore, other studies have suggested that a low-carb diet may increase our metabolism (5). This may lead to an even greater calorie burn and more efficient weight loss.
2. Diminished Appetite
What the Science Says
One of the most challenging aspects of dieting is combating feelings of hunger. However, with the low-carb diet, it is possible that hunger becomes less of a problem.
Studies on low-carb diets suggest that the approach effectively reduces hunger and promotes satiety (6).
It is thought that this occurs due to ketosis which occurs when the body cannot use carbohydrates for energy.
Ketosis is the process of converting fat into something known as ketones which can then be used as energy.
While it’s currently unclear why this occurs, it is thought that ketosis impacts appetite-regulating chemicals and hormones (7).
As mentioned previously, low-carb high-protein diets are particularly effective for weight loss. They are particularly effective for regulating appetite.
This is primarily due to the fact that protein is highly satiating and prolongs feelings of fullness. It does this by regulating two hunger hormones known as ghrelin and leptin (8).
3. Improved Cholesterol and Triglyceride Levels
What the Science Says
The benefits of the low-carb diet extend further than simply weight loss. Studies suggest that the diet can reduce both cholesterol and triglyceride levels.
Cholesterol is a molecule that plays a key role in the transportation and hormone production. There are two types of cholesterol – high-density (HDL) and low-density lipoproteins (LDL).
HDL’s are commonly referred to as “good” cholesterol whereas LDL’s are known as “bad” cholesterol.
With a low-carb diet, while LDL levels do not appear to significantly alter, HDL levels may increase (9).
Triglycerides are a combination of three fatty acids that can be found within the blood. The function of triglycerides is to store unused energy and provide the body with energy.
In a similar fashion to LDL’s, having an elevated level of triglycerides can increase the risk of health issues. However, studies suggest that the low-carb diet can reduce triglyceride levels (10).
4. Better Cardiovascular Health
What the Science Says
As highlighted in the above point, low-carb diets can positively influence HDL and triglyceride levels. A combination of these two can help to improve cardiovascular health.
Enhancing levels of HDLs has been linked with reducing the risk of cardiovascular diseases such as heart disease and stroke (11).
Similarly, decreasing triglyceride levels has also been associated with a lower risk of heart-related diseases (12).
A meta-analysis reviewed a vast quantity of research on low-carb diets. It also concluded that the low-carb diet can have a positive impact on cardiovascular health (13).
5. Reduced Blood Sugar and Insulin
What the Science Says
The low-carb diet is often prescribed to diabetics due to the impact it has on blood sugar and insulin.
Research suggests that the low-carb approach reduces blood sugar and also enhances insulin sensitivity (14).
A second study found that a low-carb diet allowed diabetics to effectively stabilize their blood sugar levels. Furthermore, some subjects were even able to begin to reverse type 2 diabetes (15).
While these findings are promising, changes to a diabetic’s nutrition must be done under the guidance and instruction of a doctor.
For non-diabetics, reducing blood sugar levels is also highly beneficial and can help facilitate weight loss. Additionally, it will also substantially reduce the risk of developing disease (16).
Will The Low-Carb Diet Help Me Lose Weight?
The low-carb diet can cause weight loss and has been advocated by many studies. Since carbs make up most of our calorie intake, reducing carb intake can create a calorie deficit.
However, following the low-carb approach does not necessarily guarantee weight loss.
As highlighted, calories are most important for weight loss. Even by following the low-carb diet, it is possible to still consume too many calories and hinder weight loss.
This is particularly true for those who consume a lot of fat as fat contains 9 calories per gram. Therefore, with a high-fat, low-carb approach, calorie intake may still be too high.
Are There Any Health Risks?
For healthy individuals, while there do not appear to be any severe health risks, some side effects may be experienced.
Considering that carbohydrates provide the body with energy, restricting them may detrimentally impact energy levels.
Other potential side effects include:
- Digestive Issues
- Flu-like Symptoms
- Muscle Weakness
It is important to consult a doctor prior to making any significant changes to our nutrition or starting a diet. This is specifically true for those with medical conditions.
How To Start A Low-Carb Diet?
Before beginning a low-carb diet, it is important to determine carb intake. How far will carbohydrate intake be restricted?
For a strict low-carb diet, carbs may be restricted to a maximum of 25 grams per day. A more liberal low-carb diet may permit up to 100 grams per day.
Once this has been determined, it is recommended to follow a meal plan that aligns with the permitted amount of carbs.
After a few weeks, if fat loss is not occurring, we should reduce carb intake further. If weight loss is taking place, the diet should be maintained until our goal weight is attained.
Typical Meal Plans
What is the best low-carb diet?
There are a number of specific low-carb diets to choose from. However, the best diet is one that suits our needs and preferences most closely.
That said, there is great benefit in consuming a low-carb, high protein diet. Research has consistently found this to be a highly effective weight-loss method (17).
How many carbs should I eat per day to lose weight?
For low-carb diets such as the Atkins or South Beach diet, the number of carbs to consume will be specified.
However, if using a low-carb approach, the amount of carbs consumed depends on personal preference. It is recommended to avoid consuming more than 100 grams per day.
How much weight can you lose on a low-carb diet?
As with all calorie-restricted diets, it is possible to lose a significant amount of weight by following the low-carb approach.
The amount of weight lost is entirely dependent on the size of the calorie deficit and the duration of the diet.
What can you eat on a low-carb diet?
Low-carb foods including meats, fish, eggs, non-starchy vegetables, nuts and seeds, oils, and some fruits.
What can’t you eat on a low-carb diet?
High carb foods including bread, pasta, starchy vegetables, cereals, some fruits, and sugary foods.
What are the side effects of the low-carb diet?
While the low-carb diet is typically safe, it may cause dizziness, headaches, fatigue, muscle weakness, nausea.
From the available research, the low-carb diet appears to be a highly effective diet for weight loss.
Carbs tend to form the bulk of our daily nutrition. Therefore, by reducing the number of carbs we consume, we also drastically reduce calorie intake thus facilitating weight loss.
However, the benefits of this approach extend further than just weight loss. The diet has been found to reduce cholesterol and triglyceride levels thus enhancing heart health.
Furthermore, it is a diet that is commonly used by diabetics to effectively regulate blood sugar levels and increase insulin sensitivity.
While the diet appears to be safe for healthy individuals, some side effects may be experienced. Therefore, it’s important to consult a doctor before starting the low-carb diet.
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