Before moving into the research studies, it is crucial to understand a low-carb or low-fat diet. There is no clear-cut definition of either of these diet types, but it is generally considered that a diet consisting of 50-100 grams of carbs is a low-carb diet, and a diet in which less than 20% of calories are coming from fats is known as the low-fat diet. A very low-carb diet is also known as a ketogenic diet. Let’s look at some of the research studies covering low-fat and low-carb diets-

1. A 2003 study published in the New Zealand Journal of Medicine found that the low-carb group lost 7 % of their total body weight, and the fat group lost only 3% after 6 months. However, after 6 months, the weight loss between both groups was almost identical. This study was conducted on 63 obese adults for 12 months. No doubt, this study proved that a low-carb diet is superior in the early phase of the weight loss journey (up to 6 months), but it produces the same result as the low-fat diet in the long term. 
2. A recent year-long study conducted on 75 people, out of which only 9 were men, also found that weight loss was higher in the low-carb group in the first 6 months, but at the 12 months mark, both low-carb and low-fat group lost almost a similar amount of weight. In this study, the low-carb group was told to have no more than 40 grams of carbs a day, and the low-fat group had less than 30% of their daily calories from fats, and their total calorie intake was 2000 calories per day. Ultimately, this trial failed because it did not go according to the design. As there was no direct control over participants’ food intake, the group supposed to take 40 grams of carbs took 93 grams of carbs on an average per day at six months in. So, it is impossible to make any conclusion from this study.    
3. A randomized control trial was conducted on 609 participants, of which 263 were males and 346 were premenopausal females. All the participants had no health conditions like diabetes or cancer. Cholesterol, etc., and their average age was 40 years. All the participants were divided into two groups- the low-fat group and the low-carb group. For the first 2 months, the low-fat group was instructed to take only 20g of fat per day, and the low-carb group had only 20g of carbs per day. Remember, after 3 months, there was no control over their macronutrient intake. For example, the low-fat group had more than 42g of fat, and the low-carb group took, on average, 96 g of carb per day. Participants were given no instruction on how many calories they needed to take a day. Still, they were instructed to maximize their fruits and vegetables and minimize their processed food intake. The significant findings of this study are as follows-

• The study found no significant weight loss difference between the low-fat and low-carb groups. The low-carb group had lost 13.2 lbs, and the low-fat group 11.7 lbs after 12 months.
• This study concluded that weight loss results from calorie restriction and mindful eating. Neither a low-carb nor low-fat diet is superior for weight loss as long as your daily calorie intake is controlled. 

4. A 6 weeks study published in the American Journal of Clinical Nutrition found that the Low carb group lost 6.2kg, whereas the low-fat group lost 6 kg of body weight after 6 weeks. The weight difference between both groups was not significant. This study was conducted on 32 adults with obesity.

5. Another study conducted in 2012 by Guldbrand H and his team also showed that low-fat and low carb lost weight over time, but the weight difference was not significant as found in other studies. In this study, the Low carb group lost 6.8 lbs, and the low-fat group lost 7.9 lbs. It was conducted on 61 individuals with type-2 diabetes.