Studies on Low Carbohydrate Diets
I know I might be dwelling a bit on this carbohydrate topic so I promise that I in my next article will write about something else, but I would like to point out a few studies conducted within the area of low carbohydrate diets and the effects they have had.
So let's start out with a paper from 2009 written by Volek et al.
titled "Carbohydrate Restriction has a More Favorable Impact on the Metabolic Syndrome than a Low Fat Diet".
Aim: To find out whether the biological markers (referring to metabolic syndrome) are improved by carbohydrate restriction.
Method: Randomised controlled trial using 40 participants with atherogenic dyslipidemia.
Participants were randomly alocated to a carbohydrate- restricted diet (%carbohydrate:fat:protein = 12:59:28) or a low-fat diet (56:24:20); both diets consisting of 1500 kcal per day.
Body mass, body composition, blood samples, oral fat tolerance test and dietary intake were assessed in all participants before and after the interventions.
In addition, physical activity routines were maintained throughout the study and recorded by the participants on a daily basis.
Results: Particpants following the carbohydrate-restricted diet had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable cholesterol levels.
Also, despite a threefold higher intake of dietary saturated fat during the carbohydrate-restricted diet, saturated fatty acids in triacylglycerol and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to participants consuming the low-fat diet.
Conclusion: The results support the use of dietary carbohydrate restriction as an effective approach to improve features of metabolic syndrome and cardiovascular risk.
Next study is written by Nielsen and Joensson (2006) titled "Low-carbohydrate diet in type 2 diabetes.
Stable improvement of bodyweight and glycemic control during 22 months follow-up".
Background: It was previously reported that 16 obese patients with type 2 diabetes, who were advised to lower their carbohydrate intake to 20 %, over 6 months achieved significantly better control of hyperglycemia and bodyweight than a control group of similar patients (n = 15), advised to follow the official dietary guidelines where 55-60 % carbohydrate is recommended.
Aim: To determine to what degree the changes among the 16 patients in the low-carbohydrate diet group at 6-months were preserved or changed 22 months after start, even without close followup.
" Method: Retrospective follow-up of previously studied subjects on a low carbohydrate diet.
The participants following the low-carbohydrate diet were advised to follow a diet containing initially 1800 kcal for men and 1600 kcal for women.
The proportions of carbohydrates, protein and fat were 20 %, 30 % and 50 % respectively.
The daily quantity of carbohydrates was 80-90 g.
The recommended carbohydrate consumption was limited to vegetables and salad.
The control group was initially advised on a diet with about the same caloric content, but the proportions of carbohydrates, protein and fat were 55-60 %, 15 % and 25-30 %.
Results: The mean bodyweight at the start of the initial study was 100.
6 ± 14.
7 kg.
At six months it was 89.
2 ± 14.
3 kg.
From 6 to 22 months, mean bodyweight had increased by 2.
7 ± 4.
2 kg to an average of 92.
0 ± 14.
0 kg.
Seven of the 16 patients (44%) retained the same bodyweight from 6 to 22 months or reduced it further; all but one had lower weight at 22 months than at the beginning.
Conclusion: A reduction in carbohydrates for patients with type 2 diabetes effectively reduces both fasting and postprandial glucose.
Therefore, advice on a 20 % carbohydrate diet with some caloric restriction to obese patients with type 2 diabetes has lasting effect on bodyweight and glycemic control.
Also, there has been no evidence of a negative cardiovascular effect among the 16 subjects.
Looking at just these 2 studies makes it clear that low-carbohydrate diets are beneficial for the majority of people, and especially for people with metabolic or chronic diseases.
However, there is a need for more research on low-carbohydrate diets and its long term effects with a larger sample size and using healthy adults in order to be more representative of the general population.
To finish this article off I just wanted to mention this news article about a woman who supposedly died from an overconsumption of soda.
So what was it about heart attacks and saturated fat? Oh no wait, soda does not contain any saturated fat, but lots of sugar and caffeine.
But then the next question is, was it actually the soda (sugar and caffeine) that killed her or was it something else? Again, it is about being critical and not taking everything at face-value when you hear and read about it in the media as they do like to throw things out of proportion.
Here is the link to the news article if you haven't read it: http://digitaljournal.
com/article/343324 Anna Kristensen
So let's start out with a paper from 2009 written by Volek et al.
titled "Carbohydrate Restriction has a More Favorable Impact on the Metabolic Syndrome than a Low Fat Diet".
Aim: To find out whether the biological markers (referring to metabolic syndrome) are improved by carbohydrate restriction.
Method: Randomised controlled trial using 40 participants with atherogenic dyslipidemia.
Participants were randomly alocated to a carbohydrate- restricted diet (%carbohydrate:fat:protein = 12:59:28) or a low-fat diet (56:24:20); both diets consisting of 1500 kcal per day.
Body mass, body composition, blood samples, oral fat tolerance test and dietary intake were assessed in all participants before and after the interventions.
In addition, physical activity routines were maintained throughout the study and recorded by the participants on a daily basis.
Results: Particpants following the carbohydrate-restricted diet had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable cholesterol levels.
Also, despite a threefold higher intake of dietary saturated fat during the carbohydrate-restricted diet, saturated fatty acids in triacylglycerol and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to participants consuming the low-fat diet.
Conclusion: The results support the use of dietary carbohydrate restriction as an effective approach to improve features of metabolic syndrome and cardiovascular risk.
Next study is written by Nielsen and Joensson (2006) titled "Low-carbohydrate diet in type 2 diabetes.
Stable improvement of bodyweight and glycemic control during 22 months follow-up".
Background: It was previously reported that 16 obese patients with type 2 diabetes, who were advised to lower their carbohydrate intake to 20 %, over 6 months achieved significantly better control of hyperglycemia and bodyweight than a control group of similar patients (n = 15), advised to follow the official dietary guidelines where 55-60 % carbohydrate is recommended.
Aim: To determine to what degree the changes among the 16 patients in the low-carbohydrate diet group at 6-months were preserved or changed 22 months after start, even without close followup.
" Method: Retrospective follow-up of previously studied subjects on a low carbohydrate diet.
The participants following the low-carbohydrate diet were advised to follow a diet containing initially 1800 kcal for men and 1600 kcal for women.
The proportions of carbohydrates, protein and fat were 20 %, 30 % and 50 % respectively.
The daily quantity of carbohydrates was 80-90 g.
The recommended carbohydrate consumption was limited to vegetables and salad.
The control group was initially advised on a diet with about the same caloric content, but the proportions of carbohydrates, protein and fat were 55-60 %, 15 % and 25-30 %.
Results: The mean bodyweight at the start of the initial study was 100.
6 ± 14.
7 kg.
At six months it was 89.
2 ± 14.
3 kg.
From 6 to 22 months, mean bodyweight had increased by 2.
7 ± 4.
2 kg to an average of 92.
0 ± 14.
0 kg.
Seven of the 16 patients (44%) retained the same bodyweight from 6 to 22 months or reduced it further; all but one had lower weight at 22 months than at the beginning.
Conclusion: A reduction in carbohydrates for patients with type 2 diabetes effectively reduces both fasting and postprandial glucose.
Therefore, advice on a 20 % carbohydrate diet with some caloric restriction to obese patients with type 2 diabetes has lasting effect on bodyweight and glycemic control.
Also, there has been no evidence of a negative cardiovascular effect among the 16 subjects.
Looking at just these 2 studies makes it clear that low-carbohydrate diets are beneficial for the majority of people, and especially for people with metabolic or chronic diseases.
However, there is a need for more research on low-carbohydrate diets and its long term effects with a larger sample size and using healthy adults in order to be more representative of the general population.
To finish this article off I just wanted to mention this news article about a woman who supposedly died from an overconsumption of soda.
So what was it about heart attacks and saturated fat? Oh no wait, soda does not contain any saturated fat, but lots of sugar and caffeine.
But then the next question is, was it actually the soda (sugar and caffeine) that killed her or was it something else? Again, it is about being critical and not taking everything at face-value when you hear and read about it in the media as they do like to throw things out of proportion.
Here is the link to the news article if you haven't read it: http://digitaljournal.
com/article/343324 Anna Kristensen