Real People's Actual Weight Loss During One Month on a Low Carb Diet
Diet books make it sound like most people lose a lot more weight on the diet they are promoting than real people really do. This makes a lot of people assume they are failing on a diet when, in fact, they are making normal progress.
Where did we get our data?
Between September 1, 2002 and January 31, 2003 the alt.support.diet.low-carb ran monthly "Five Pound Challenges" where participants posted their starting weight and set a goal weight for the month that was five pounds lighter. Participants updated their statistics as the month progressed. In addition, participants reported when they had started their low carb diet.
I analyzed five months worth of the posted Challenge data to see what really happens when people eat a low carb diet. You will see these results in the graphs displayed below.
Though many individuals participated in more than one monthly challenge the data was only analyzed on a per month basis. Data of a person who contributed data to more than one monthly challenge is treated as a separate set of data points.
How was the data analyzed?
A total of 226 individual reports with all the data filled in were tabulated. These reports were then broken into two groups. The first group consisted of "experienced dieters." The second were "newbie dieters."
Experienced dieters are individuals who had been on the diet for at least one month at the time that the monthly challenge began. For example, a person who began their diet on November 28, 2002 would be considered experienced in the January challenge which ran from 1/1/03 to 1/31/03.
Newbie dieters are people who had been on the diet a month or less when the challenge began. A person who began their diet on December 1, 2002 would be considered a "newbie" for the January 2003 challenge.
The data in both groups was then further broken down by the starting weight of the participant at the beginning of the challenge month. In addition, several categories are broken down by gender where gender can be determined from the participant's name. Where gender is not clear from the name, the participant is not included in the gender breakdown.
What does the data show?
The graphs below summarize the data, showing the highest, lowest, and median pounds lost for various sub-categories of dieters. Medians were used rather than averages as being a more accurate gauge of weight loss. However, it turns out that the averages were very close to the medians in all the samples studied.
How much was the median weight loss?
The median weight loss for all groups of experienced dieters fell between 2.25 and 7.25 lbs with the median weight of each subgroup rising as the starting weight of the dieters in the group increased.
The median weight loss for the entire group of experienced dieters was 4 lbs per month.
The median weight loss for all dieters who had been on the diet less than a month at the start of the diet month was only slighlty higher at 6 pounds.
The differences between men and women were minor in every group with significant male/female participation with a variation of not more than a pound in the medians. However, there was significantly more female participation in this study than male.
Some dieters were stalled--i.e. they experienced no weight loss for the month--in every subgroup reporting except among experienced dieters weighing over 300 lbs at the start of the month.
ConclusionsA realistic monthly weight loss goal for the low carb dieter who has been dieting for more than two weeks would appear to lie between 2 and 6 lbs, with heavier dieters losing a bit more than thinner ones.
This isn't the dramatic weight loss most low carbers expect based on the big losses that many dieters experience in their first two weeks, but the amounts shown here match those reported by dieters in all successful weight loss programs and are in line with the amounts of weight that you can expect to lose on any diet, once it is fat rather than water you are losing.