UPDATE: Added 7 more data records collected from posting poll of Low Carb Friends discussion board. All statistics were reanalzyed, but the medians did not change.
I also added an analysis of the data from those who maintained weight losses for 5+ years.
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I've taken the information contributed by people who responded to the poll in the comments posted to the previous post and done what I could to standardize the responses in a way that makes it possible to analyze this data.
Fifty-one people contributed data. Of these 49 had Type 2, 1 had MODY and 1 had Type 1.
Two reported a weight gain.
One maintained a stable weight for 40 years but is probably not a Type 2.
Three reported no weight loss or a completely regained the weight they originally lost.
Weight Loss
Of those who lost weight and maintained some of that loss, 42 contributed information which allowed me to calculate what percentage of their starting weight they were able to lose and maintain.
The time framee people reported for their diet ranged from 40 years to just started, with a median time of 2 years.
The amount of weight loss that had been maintained ranged from 190 to 6 pounds, with a median maintained loss of 50 lbs.
The percentage of starting weight that was maintained ranged from 50% to 3% with a median maintained percentage of starting weight lost of 20%. The standard deviation of percentage of starting weight lost and maintained, which is a measure of how closely these percentages cluster around the mean was 10.5%. So most people who maintained maintained a weight loss that was between 9% and 31% of their starting weight.
This is probably the most important statistic of all as it gives you a very good idea of what a realistic weight loss is that you can expect to maintain.
People lost weight using a variety of techniques. Cutting back on carbohydrates was the most common. Thirty-eight respondents reported following some form of a Low Carb diet. Thirteen people reported using ketogenic diets--Atkins, Bernstein or under 60 grams a day of carbohydrate. However, it is possible some of the others who merely reported "low carb" diets were also eating ketogenic diets.
Fifteen respondents attributed weight loss to portion control or counting calories. Ten cited walking. Ten cited "exercise." These methods were often combined and occurred with and without carbohydrate restriction. The biggest weight loss was reported by someone who had Gastric Bypass who reports that severe health problems resulted.
Weight Regain
Twelve people reported significant weight regain. In general, the greater percentage of original body weight they had lost, the more they were likely to regain.
What really stands out is that after regaining, the weight at which these dieters who regained weight were finally able to maintain at was very close to a 20% loss from their starting weight.
This suggests very strongly that a 20% loss from starting weight is the most maintainable weight loss for most people.
Long Term Maintainers
There were 13 people who maintained their weight loss for 5 or more years. This is 25% of all people reporting and a remarkably high percentage. This result might be skewed by the self-reporting nature of this survey.
The largest percentage loss (excluding the loss from surgery) was 33% but 7 of the 10 for whom I have weight loss percentage information maintained a weight loss of 20±3 lbs of their starting weight. This is yet another bit of information that points to 20% as the ideal weight loss percentage to shoot for.
Blood Sugar Control
Five respondents out of 44 who had Type 2 reported that their blood sugar control had improved and they could tolerate more carbohydrate. One with IGT reported significant improvement.
Another 4 reported that they could tolerate slightly more carbohydrate.
Thirty-five reported no change in blood sugar control after weight loss with three stating emphatically that it did not help their blood sugar at all or that blood sugar control got worse.
However, the most important statistic relevant to blood sugar control was that all but 7 respondents reported that they continued to control their carbohydrate intake. So reported blood sugar "improvement" in most cases was dependent on continuing to eat a carbohydrate restricted diet, not because of any true change in their ability to metabolize carbohydrates.
Conclusions
These results suggest that a realistic weight loss that you can expect to maintain would be one that ranged between 10 and 30% of your starting weight, with 20% being the most likely maintainable percentage of weight loss.
They also suggest that losing weight will rarely normalize your blood sugar or "reverse" your diabetes. However, if you use a low carbohydrate diet approach of any type, you can expect to improve your blood sugar control if you continue to stick to some form of carbohydrate restriction.
Those who lost weight relying on portion control and/or exercise may also have to maintain those behaviors to retain any improvements in blood sugar control.
There is no clear cut weight loss advantage to any particular diet plan, as far as producing weight loss. Low carb diet plans appear to be somewhat easier to maintain long term if they lower carbohydrate enough to keep blood sugars controlled and avoid the hunger several people reported with higher carbohydrate weight loss diets.
People lost and maintained weight loss for several years on very low carb and moderate carb plans. Weight gain occurred on various plans too, independent of the carbohydrate intake.
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Note: Please feel free to continue to contribute data to the poll in the previous blog post. If enough new information comes in, I will reanalyze it.
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