Low-carb diets have proven to be good for weight loss. But, when limiting carbs, you may wonder if it's better to eat more protein or fat to help you reach your goals. As it turns out, it all depends on you and your taste buds -- both low-carb, high-fat and low-carb, high-protein diets can help you lose weight. If you need help designing a low-carb plan based on your food preferences, see a registered dietitian for help.
Low-Carb Diet Basics
There's more than one way to do a low-carb diet. But, most health care professionals agree that reducing your carbs to 50 to 150 grams a day constitutes a low-carb plan. Some plans recommend you go even further and limit carbs to 20 to 50 grams. These very-low-carb diets are popular among the commercial low-carb diets, such as Atkins and South Beach, and are meant to get you into ketosis, which is a state where your body is forced to burn fat for fuel because there isn't enough glucose. Often, carbs are added back after you've lost the weight on these types of diets, but still remain in the low-carb range.
Low-Carb, High-Fat Diet
The low-carb, high-fat diet, which is also known as a ketogenic diet, is what most people do when they follow a low-carb diet. They shift their calories from carbs to fat, increasing their intake of higher-fat protein foods, full-fat cheeses and nuts and adding more fat to their food such as butter, oil and mayonnaise.
A low-carb, high-fat diet may be more effective at helping with weight loss than a low-fat diet, according to a 2013 review study published in the British Journal of Nutrition. This study found that people following a low-carb, high-fat diet lost more weight than those following a low-fat diet. Additionally, the people following a low-carb, high-fat diet also saw an improvement in blood pressure and good -- or HDL -- cholesterol levels.
Low-carb diets are already good at helping keep hunger away, but so is protein. Upping the protein content of your low-carb diet may be even more helpful in your weight-loss journey if you're struggling with hunger. A 2008 study published in The American Journal of Clinical Nutrition looked at a group of obese men on low-carb, high-protein diets and high-protein moderate-carb-restricted diets, comparing each diet's effects on weight loss and appetite. Calories were not restricted. The researchers found that the combination of low-carb and high-protein helped keep hunger under better control than the high-protein, moderate-carb diet, so the group ate less and lost more weight.
However, while adding more protein to your diet may keep hunger away, eating too much protein -- more than 35 percent of calories from protein -- can be bad for your health. Excessive protein causes elevated ammonia and amino acid levels and may cause nausea, vomiting, diarrhea or even death, according to a 2006 report published in the International Journal of Sport Nutrition and Exercise Metabolism.
Choosing Your Low-Carb Diet
When it comes to weight loss, either diet works. However, you might want to discuss the diet with your doctor before making a decision. If you have issues with your kidneys, getting too much protein may worsen the condition, and you may be better off following the low-carb, high-fat diet. Additionally, if you're concerned with all the saturated fat in the high-fat version, you may prefer eating more protein. Adding healthier high-fat foods such as salmon, tuna and avocados may, however, decrease saturated fat intake while still following the higher-fat plan.
In any event, the best weight-loss diet is the one you can stick to. So, ultimately it may come down to personal taste, especially since both seem to work at not only helping you lose the weight, but also keeping a lid on hunger.
- American Journal of Clinical Nutrition: Low-Carbohydrate Nutrition and Metabolism
- Authority Nutrition: The 8 Most Popular Ways to do a Low-Carb Diet
- Diet Doctor: Low-Carb Diet for Beginners
- British Journal of Nutrition: Very-Low-Carbohydrate Ketogenic Diet v. Low-Fat Diet for Long-Term Weight Loss: A Meta-Analysis of Randomised Controlled Trials
- The American Journal of Clinical Nutrition: Effects of a High-Protein Ketogenic Diet on Hunger, Appetite and Weight Loss in Obese Men Feeding Ad Libitum
- International Journal of Sport Nutrition and Exercise Metabolism: A Review of Issues of Dietary Protein Intake in Humans
- American Journal of Clinical Nutrition: Protein, Weight Management and Satiety