A low-carb diet and workout routine might be exactly what you need to lose stubborn fat. However, there are some things you should know before getting started. Low-carbohydrate diets, for example, may affect your ability to build lean mass and hamper physical performance.
Good Carbs vs. Bad Carbs
Carbohydrates are often blamed for weight gain, but eating a low carb diet and exercise can still work. You may just need to be more thoughtful about the carbs you are eating. While it's true that white bread, pasta, cookies and other high-carb foods may contribute to obesity, not all carbs are created equal. As Harvard Health Publishing notes, whole foods are rich in complex carbs that support overall health. These nutrients play a key role in sports performance, leading to greater energy and reduced fatigue.
The U.S. Anti-Doping Agency points out that carbs may increase endurance and replenish glycogen stores. Ideally, athletes should aim for 3 to 12 grams of carbohydrates per kilogram of body weight. The longer and more intense your workout, the more carbs you need.
Athletes have higher nutritional requirements than the average person, which means that if you're eating low carb, weight training may be more of a challenge. A bodybuilder, for example, can afford to eat a bowl of white rice after hitting the gym. Her body needs those extra carbs to recover from training and fix damaged tissues. The same goes for runners, powerlifters, swimmers and other athletes who rely on carbs to fuel their workouts.
If you're trying to get leaner, you can cut down on carbs to reduce your energy intake and flush out water. Bodybuilders and fitness models use this approach before competitions.
After ingestion, carbohydrates are converted to glycogen. Each gram of glycogen holds approximately 3 grams of water, explains a review published in the European Journal of Applied Physiology in December 2017. Therefore, you may lose some water weight while on a low-carb diet.
Are Low-Carb Diets Effective?
Whether you want to lose 10 or 50 pounds, if you cut out cookies, bagels, soda and other foods or beverages loaded with carbs, you'll take in fewer calories. At the same time, you'll eliminate excess water and are likely to look leaner overall. However, there are some aspects you need to consider before taking the plunge.
First of all, it's necessary to increase your protein or fat intake when cutting down on carbs, as your body still needs a source of energy. Protein and carbs have 4 calories per gram, while fat delivers 9 calories per gram, as reported by the USDA. Any of these nutrients can be used for fuel, according to Carleton College.
Protein, for example, helps preserve lean mass, inhibits hunger and keeps your metabolism up, explains a review published in the British Journal of Nutrition in August 2012. A daily intake of 1 to 2 grams of protein per kilogram of bodyweight is clinically proven to improve body composition, or fat-to-muscle ratio.
Consider replacing refined carbs with plant-based protein. Soybeans, tofu, tempeh, lentils, kidney beans and chickpeas are all a healthy choice. In addition to protein, these foods are rich in fiber and other key nutrients that may improve diet quality. Due to their high fiber content, they are more filling than refined carbs, such as white rice or pasta.
Dietary fat is more nutrient-dense, but it may still help you lose weight. A typical ketogenic diet is moderate in protein, low in carbs and high in fat.
According to a review featured in the International Journal of Environmental Research and Public Health in February 2014, ketogenic diets may facilitate weight loss and improve metabolic health. At the same time, they promote satiety and enhance your body's ability to burn fat. Some versions restrict carbs to only 10 percent of your daily energy intake, reports a September 2018 review in the Indian Journal of Medical Research. Unfortunately, they may not be safe in the long run.
Low-Carb Diet and Exercise Considerations
Depending on your preferences, you can cut down on carbs gradually and increase your protein intake, or go on a ketogenic diet. Either way, it's important to consider your lifestyle and exercise habits. Going on a low-carb diet and weight training, for instance, requires some planning.
A small study published in the Journal of the International Society of Sports Nutrition in April 2019 on CrossFit athletes points out that ketogenic diets may hinder exercise performance, especially during high-intensity training. It all comes down to your body's ability to use fat for fuel.
According to the National Academy of Sports Medicine (NASM), athletes with depleted muscle glycogen stores — a common side effect of low-carb diets — are more likely to experience fatigue and diminished performance. As the researchers note, dietary fat requires more oxygen to produce energy compared to carbohydrates. Therefore, you must work out at a higher intensity than usual in order to burn fat.
As the NASM points out, excess calories of any type can lead to weight. While it's true that you may need to eat more protein or fat while on a low-carb diet, you shouldn't go overboard.
Beware that muscle building is more difficult while on a low-carb diet. In a small study, men who went on a ketogenic diet and engaged in strength training experienced a reduction in body fat mass and visceral fat. Their protein intake was 2 grams per kilogram of body weight per day, which allowed them to preserve lean mass. These findings were published in the Journal of the International Society of Sports Nutrition in July 2018.
A low-carb, high-fat diet may help prevent muscle loss, but it's unlikely to increase muscle mass, according to the above study. Furthermore, dietary fat isn't an optimal source of fuel during high-intensity exercise, states the University of Minnesota. Therefore, if your workouts are intense, you may not be able to perform at your peak while on a ketogenic or very-low carbohydrate diet.
Strive for Balance
As Harvard Health Publishing notes, low-carb diets are not sustainable in the long run. These weight-loss plans tend to be restrictive and can lead to nutrient deficiencies. Ketogenic diets, for example, are extremely low in fiber, causing constipation in more than one-third of cases, reports a review published in the journal Canadian Family Physician in December 2018.
A more balanced approach is the cyclical ketogenic diet, which alternates between high- and low-carb diets, explains the Indian Journal of Medical Research. Similarly, you can choose a targeted ketogenic diet and consume carbs around your workouts. This way, you'll replenish your glycogen stores and have the energy needed for intense training.
Remember that not all carbs are harmful. To lose weight, limit refined carbs and watch your energy intake. Get your calories from whole and minimally processed foods, such as poultry, fish, fresh fruits, leafy greens and eggs. Eat nuts and seeds in moderation to fill up on healthy fats and keep hunger at bay. Consider cutting back on carbs on your off-training days when your body needs less energy.
- Harvard Health Publishing: "The Smart Way to Look at Carbohydrates"
- U.S. Anti-Doping Agency: "Carbohydrates – The Master Fuel"
- European Journal of Applied Physiology: "The Availability of Water Associated With Glycogen During Dehydration: A Reservoir or Raindrop?"
- USDA: "How Many Calories Are in One Gram of Fat, Carbohydrate, or Protein?"
- Carleton College: "Energy Sources in Foods: Carbohydrates, Fat, and Protein"
- British Journal of Nutrition: "Dietary Protein – Its Role in Satiety, Energetics, Weight Loss and Health"
- International Journal of Environmental Research and Public Health: "Ketogenic Diet for Obesity: Friend or Foe?"
- The Indian Journal of Medical Research: "Ketogenic Diets: Boon or Bane?"
- Journal of the International Society of Sports Nutrition: "Effect of a Four-Week Ketogenic Diet on Exercise Metabolism in CrossFit-Trained Athletes"
- National Academy of Sports Medicine: "A Low-Carb Diet for Athletes?"
- Journal of the International Society of Sports Nutrition: "Efficacy of Ketogenic Diet on Body Composition During Resistance Training in Trained Men: A Randomized Controlled Trial"
- University of Minnesota: "The Effects of Low Carbohydrate Diets on Endurance Performance"
- Canadian Family Physician: "Ketogenic Diet for Weight Loss"
- American Journal of Clinical Nutrition: "Plant- and Animal-Protein Diets in Relation to Sociodemographic Drivers, Quality, and Cost: Findings From the Seattle Obesity Study"