When it comes to losing weight, trying to choose the best plan can be a daunting task. Should you follow government guidelines and go low fat? Should you go with the much touted low carb plans, such as Atkins 40 and Ketogenic Diet?
While many health organizations believe that an increase in the amount of fat typically consumed in the SAD (Standard American Diet) is the driving force behind obesity, there is a fairly new trend which has found that it is an excess consumption of carbohydrates that is actually to blame for the millions of overweight people around the globe.
Let's take a look at the truth behind these two approaches to weight loss by looking at scientific studies, published in well respected, peer reviewed journals.
Keep in mind that most of these studies involved people who were obese and had serious health problems because of it, such as type 2 diabetes or metabolic syndrome. Most of these studies looked at not only weight loss, but blood sugar levels, LDL and HDL cholesterol levels, and more.
This study splits 63 people into two groups at random. One group followed a low fat, low calorie diet, the other group, a low carb diet. The study was 1 year in length.
The Results: The low carb group lost more weight (7.3% of total body weight) compared to the low fat group (4.5% of total body weight) but only for the first 6 months. After the 6 month point, there was little difference between the two groups, other than the low carb group had better triglyceride and HDL cholesterol levels. Otherwise, the results were the same.
We can conclude from this study that low carb diets definitely gave better results in terms of weight loss, but only for the first 6 months.
This study was larger, using 132 persons who were very obese (with a BMI of at least 43) were separated into a low fat group or low carb group. This study lasted 6 months.
The Results: The low carb group lost an average of 12.8 pounds (5.8 kilos), while the low fat, low calorie group lost only 4.2 pounds (1.9 kilos). This is a significant difference!
It's interesting to note that the low fat group had slightly worse insulin sensitivity levels, while the low carb group saw improvement. Triglycerides and insulin levels were reduced for those eating low carb, while the numbers were slightly worse for those eating low fat.
It's easy to see in this study that the low carb group not only lost more weight, but they had improved health as well.
A group of 30 overweight teens were separated into two groups; one eating low fat, one low carb. The study was only 12 weeks in length.
The Results: The low carb group lost 21.8 pounds (9.9 kilos), while the low fat group lost only 9 pounds (4.1 kilos). This is a significant difference!
The low carb group not only lost 2.3 times as much weight, but they also had significantly lower levels in their triglycerides and non-HDL cholesterol.
Sixty overweight persons were separated into two groups and were given either a low carb diet high in monounsaturated fats, or a low fat diet. Both groups were given calorie restrictions. This study was 12 weeks in duration.
The Results: The low carb group lost, on average, 13.6 pounds (6.2 kilos), while the low fat group lost 7.5 pounds (3.4 kilos). While it’s easy to see that there is a substantial difference in the amount of weight lost (with the low carb group losing almost twice as much as the low fat group) there were other markers that were significant:
In this study, 120 individuals who were classified as being overweight with elevated blood lipids were separated into a low carb or low fat diet group. The low fat diet was calorie restricted; the low carb diet was not. This study was 24 weeks in length.
The Results: The low carb group lost 20.7 pounds (9.4 kilos), compared to the low fat group, which lost 10.6 pounds (4.8 kilos) on average. The low carb group not only lost significantly more weight, but they also had more improvement in the area of HDL cholesterol and blood triglyceride levels.
This study involved 119 overweight persons who were divided into two groups; low carb and low fat. The low fat group was to follow a calorie restrictive diet as well. The study was 6 months in length.
The Results: The low carb group lost 28.4 pounds (12.9 kilos) on average, while the low fat group lost 14.7 pounds (6.7 kilos). This means that, even through the low fat group consumed fewer calories, a low carb diet caused people to lose almost twice as much weight.
This was an interesting study which divided 311 obese or overweight premenopausal women into randomized groups of 4. This looked at the Atkins diet (low carb), a traditional low fat, vegetarian Ornish diet, the Zone diet or the LEARN diet. The Zone and LEARN diet were calorie restricted, the other two were not. This study lasted 12 months.
The Results: The Atkins (low carb) dieters lost the most weight with 10.3 pounds (4.7kilos) being the average. The Ornish dieters lost an average of 4.9 pounds (2.2kilos), the LEARN dieters lost 5.7 pounds (2.6 kilos), and the Zone dieters lost 3.5 pounds (1.6 kilos). Again, this difference in weight was only significant during the first 6 months. After a 6 month period, there was no noticeable difference.
The Atkins group, however, did have the most improvement in blood pressure, HDL cholesterol and triglycerides. None of the other groups had any significant difference in this area after 12 months.
This 3 month study divided 13 non-diabetic persons and 13 persons who had been diagnosed as being diabetics and randomized them to eat a low carb diet or a diet which followed the Diabetes UK eating recommendations (basically a low fat, restricted calorie diet).
The Results: The low carb group lost 15.2 pounds on average (6.9 kilos), while the low fat group lost only 4.6 pounds (2.1 kilos). There was no difference between the groups when it came to other health markers, only that the low carb group lost almost 3 times as much weight.
In this study, 322 obese individuals were randomized into three groups. One group was given a low carb diet, the other a low fat, calorie restricted diet, and the third group a calorie restricted Mediterranean diet. This was a long term study of 2 years.
The Results: The low carb group lost an average of 10.4 pounds (4.7 kilos) while the Mediterranean diet group lost an average of 9.7 pounds (4.4 kilos) and the low fat group lost the least amount of weight with an average of 6.4 pounds (2.9 kilos).
The low carb group also had greater improvements in their HDL and triglyceride scores.
Our last study involved 118 persons with abdominal obesity. Subjects were split into two randomized groups and given a low carb or low fat diet plan for one year. Both groups had calorie restrictions.
The Results: The low carb group lost 32 pounds on average (14.5 kilos), while the low fat group lost 25.3 pounds on average (11.5 kilos).The low carb group also had significantly lower levels of triglycerides and greater increases in both HDL and LDL cholesterol levels when compared to the low fat group.
All of the above studies are controlled, randomized studies, which are the gold standard of science. You can also see that all the studies were published in peer reviewed highly respected medical journals.
Isn't it time we retired that old "fat makes you fat" line? These studies, and the hundreds of others like them, show that low carb is far more effective than low fat when it comes to losing weight and improving cholesterol and triglyceride levels.