The reality is that you can lose weight on any diet. But, when it comes to improving health, one may be better than the other.
Low-carb and low-fat diets are two popular approaches that aid weight loss.
A low-fat diet, in particular, is a common practice in the bodybuilding community (except for a few who follow a ketogenic approach while doing body recomposition) and in those who fear fat.
On the other hand, a low-carb diet is used by individuals trying to control their blood glucose and reduce their risk of getting diabetes and heart disease.
You might be wondering which dietary strategy is more beneficial for your health — is it low-carb or low-fat? This article compares low-carb vs low-fat diet diets, starting with their definition, and discusses their effects on weight loss, body fat, metabolic health, and satiety.
Low-carb diets limit a person’s intake of carbohydrates, which are found in whole and processed foods like bread, pasta, grains, cereals, pastries, potatoes, corn, and most sweet fruits.
At the same time, dietary fat is increased to serve as an energy replacement for carbs. In contrast, people on high-carb diets follow the age-old belief that carbs are the body’s main energy source[*].
Low-carb diets are further classified into two types:
- The ketogenic diet, a very low-carb approach in which carbs are reduced to a total of 20-50 grams per day to induce ketosis. Ketosis is a normal metabolic state where you burn your stored body fat, causing ketones to rise[*].
- A standard low-carbohydrate diet, where you can consume up to 130 grams of carbs per day. This does not always result in ketosis, depending on whether your glycogen stores (the storage form of carbs) are full or depleted. Regardless, ketosis is not the goal of using this approach[*].
In addition to increasing fat, those on low-carb diets up their protein intake by going over the recommended dietary allowance or RDA of 0.8 grams of protein per kilogram of body weight[*]. This is to preserve lean muscle mass and maintain optimal function during weight loss[*].
A low-carb diet food list includes a wide variety of meats, poultry, fish, seafood, eggs, leafy green vegetables, berries, nuts, seeds, animal fats, and unprocessed cooking oils.
A low-fat diet is an eating plan that limits the amount of dietary fat you eat, whether these are good or bad fats. People on low-fat may increase their protein and carbs (or keep carbs at moderate amounts) depending on their goal.
Reducing fats is often done to cut calories for weight loss — since fat has more calories per gram (9 calories) than carbs and protein (4 grams). Furthermore, some go fat-free because of the belief that “eating fat makes you fat” or “fat clogs your arteries,” thereby leading to heart disease and stroke.
Diets that fall under the low-fat category focus on plants and lean meats. For that matter, a low-fat diet food list includes grains, rice, beans, legumes, light or fat-free dairy, egg whites, chicken breast, and lean types of fish (tilapia, cod, and flounder).
Those considering this diet should be aware of the possible risks of consuming too little fat.
Important: Since fat serves vital functions in your body — such as producing hormones, providing energy, and absorbing fat-soluble vitamins (A, D, E, K) — limiting it can be problematic.
In addition, many low-fat versions of foods like breakfast cereals, yogurts, salad dressings, and skim milk tend to be higher in sugar and ingredients that are bad for your health.
Unfortunately, people sometimes think they’re making a better choice by going for the low-fat varieties — when in reality, they’re adding more sugar to their diet[*].
Should you follow a low-carb or low-fat diet to lose weight? For those whose goal is weight loss, findings from multiple studies suggest that both diets work.
Moreover, the low-carb diet is more effective for inducing weight loss in a short period of time. This is commonly seen in people who experience a massive loss of “water weight” at the start of a ketogenic diet (since excess carbs make you retain water, in addition to promoting body fat storage).
In a randomized controlled trial, 63 obese males and females were randomly assigned to a low-carb diet and a low-calorie, low-fat, and high-carb typical diet. Results showed that those on a low-carb diet lost more weight within the first 6 months. This was despite the fact that they didn’t restrict fats and protein[*].
Another interesting finding was that those on low-carb experienced decreases in their serum triglycerides and increases in their HDL cholesterol — which suggests that low-carb diets reduce your risk of heart disease[*].
In another study, 15 healthy/overweight men and 13 premenopausal women were randomly assigned to a low-fat or very low-carb diet (to induce ketosis). Based on the results, short-term keto diets outperform low-fat diets despite the men consuming more calories[*].
One explanation is that ketones produced in very low-carb diets, particularly BHB ketones, may suppress appetite[*].
The verdict: Low-carb or low-fat for weight loss is equally effective, but low-carb diets are better for losing more weight in a short period.
Fat loss refers to a reduction of your body fat, and not just water weight. Between fat loss and weight loss, fat loss is associated with lower inflammation and improved health[*].
Many studies indicate that between low-carb or low-fat for fat loss, low-carb diets are the better choice.
The same study mentioned above, which involved 15 men and 13 women, found that the low-carb group didn’t just lose weight — they also lost more fat mass, especially in their abdominal area, than those in the low-fat diet group[*].
A 2008 study was done on individuals who followed a very low-carb diet which included lots of saturated fat. Their macronutrient percentages were as follows: 4% carbs, 35% protein, and 61% fat (with 20% being saturated fat)[*].
Based on the results, these individuals had greater reductions in weight, BMI, and abdominal fat than the other group that followed a typical high-carb diet low in saturated fats[*].
Contrary to popular belief, eating fat does not cause you to store fat. Moreover, findings from a study suggest that low-carb dieters who consumed high amounts of saturated fat had better blood lipid levels[*].
Here’s more information about saturated fat, including new guidelines from the Journal of the American College of Cardiology.
The verdict: Cutting carbohydrates while increasing dietary fat (including saturated fat) is more effective for lowering your body fat.
Being metabolically healthy means that your blood sugar, blood pressure, and cholesterol fall within the normal ranges.
Low-carb and low-fat diets improve metabolic health markers differently. More specifically, low-carb diets prove to be better at improving them.
For example, a study conducted on severely obese subjects with a high prevalence of diabetes and metabolic syndrome revealed that restricting carbs induced greater weight loss. Plus, their fasting blood glucose, insulin levels, and triglycerides dropped lower than the subjects in the low-fat group[*]. Although the blood pressure readings in both groups decreased, no significant differences were noted.
Another study on a low-carb keto diet (<20 grams of carbs a day) versus a low-glycemic index diet (55% of calories from carbs) showed greater improvements in the health markers of those in the low-carb group. Their hemoglobin A1c decreased by 1.5% and most of them were able to reduce or stop their diabetes medications[*].
The verdict: Research suggests that diets that are lower in carbs win in terms of reducing blood sugar, insulin, and triglycerides. Furthermore, they may even help a person reverse type 2 diabetes.
Low-carb diets tend to increase fat and protein macros, which promote satiety and control appetite. This is why people who do low-carb properly find that they can sustain it long-term since they don’t always feel hungry.
Another reason, as mentioned earlier in this article, is that beta-hydroxybutyrate or BHB ketones cause a reduction in hunger. In fact, an eight-week study on the keto diet found that ghrelin — a hormone released by your stomach that stimulates appetite — was suppressed during ketosis[*].
Calories aren’t restricted on low-carb diets, unlike low-fat diets where individuals often track food intake and calories, which leads them to feel ravenous all the time. In a study on calorie restriction, participants had an increased desire to eat at month 6 in both calorie-restricted and low-calorie groups[*].
The verdict: Low-carb diets are better at reducing hunger than low-fat diets, which often involve counting calories to lose body fat.
When it comes to choosing between low-carb vs low-fat, research shows that both dietary approaches can help you lose weight and body fat. Furthermore, low-carb diets are more effective at burning fat while also keeping you satiated due to the presence of ketones and the increase in protein and fat macros.
Findings also suggest that low-carb diets benefit metabolic health by lowering blood glucose, insulin, and triglycerides. (Because an increase in these markers can put you at risk of diabetes, heart disease, and stroke.)
Before starting any diet, remember to do research, speak with a doctor (for example, someone with experience with low-carb), and listen to your body.