low carb diet studied in T2D ... are they getting it?

[foxl]

Diabetes Care 32.7 (July 2009): p1147(6). (5242 words)
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Author(s): Nichola J. Davis, Nora Tomuta, Clyde Schechter, Carmen R. Isasi, C.J. Segal- Isaacson, Daniel Stein, Joel Zonszein and Judith Wylie-Rosett.
Document Type: Magazine/Journal
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Full Text :COPYRIGHT 2009 American Diabetes Association OBJECTIVE--To compare the effects of a 1-year intervention with a low- carbohydrate and a low-fat diet on weight loss and glycemic control in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS--This study is a randomized clinical trial of 105 overweight adults with type 2 diabetes. Primary outcomes were weight and A1C. Secondary outcomes included blood pressure and lipids. Outcome measures were obtained at 3, 6, and 12 months.

RESULTS--The greatest reduction in weight and A1C occurred within the first 3 months. Weight loss occurred faster in the low-carbohydrate group than in the low-fat group (P = 0.005), but at 1 year a similar 3.4% weight reduction was seen in both dietary groups. There was no significant change in A1C in either group at 1 year. There was no change in blood pressure, but a greater increase in HDL was observed in the low-carbohydrate group (P = 0.002).

CONCLUSIONS--Among patients with type 2 diabetes, after 1 year a low- carbohydrate diet had effects on weight and A1C similar to those seen with a low-fat diet. There was no significant effect on blood pressure, but the low-carbohydrate diet produced a greater increase in HDL cholesterol.

:eek: really?

[fgummett]

I just find it puzzling why a diet that is (by the ADA's own admission) at the very least as good as the low-fat one promoted by many health establishments, is given such a bad rap?

I agree that an higher HDL is significant and question why it seems to be dismissed so lightly here.

I'd also suggest that the initial improved weight-loss and A1C over the first thee months is significant both from quickly establishing an improved BG and from a personal motivation standpoint.

As for what happens after the initial three months I have to wonder if this was a low-carb "a la Atkins" where carbs are gradually reintroduced or if they stayed on the same level of carbs for the entire year?

[foxl]

I suspect the positive outcome was understated for a reason, Frank ... it is a freely-available journal though, I think, if you have time to read the whole study!

[fgummett]

OK.. I found it on-line here : Comparative Study of a One Year Dietary Intervention of a Low-Carbohydrate to a Low-Fat Diet on Weight and Glycemic Control in Type 2 Diabetes ? Diabetes Care (http://care.diabetesjournals.org/content/early/2009/04/14/dc08-2108.full.pdf+html)

Interesting read through -- only about 100 participants, not blinded but hard to do that with diet, also relied on patient food records which they mention along with the usual distrust "Participants may not have fully recalled their dietary intake and in addition may have changed their dietary intake for the day prior to their scheduled appointment."

As for the low-carb approach: "The low-carbohydrate diet was modeled after the Atkins diet and was initiated with a 2 week phase of carbohydrate restriction of 20-25 grams daily depending on baseline weight. As participants achieved weight loss, they were able to increase carbohydrate intake at 5 gram increments each week." So while the low-fat arm would have maintained a constant ratio of fat, protein and carbs, the low-carb arm gradually increased their carbs based on weight loss... so the more weight they lost, the more carbs they could eat!

They go on to say "all participants received 45 minutes of individual dietary instruction by a registered dietitian and were given a specific gram allowance of carbohydrates or fat to achieve a 1 pound weight loss each week." which sounds like calorie counting to me.

But here is an interesting snippet which failed to make it to the conclusion... although the A1C was comparable in both groups at the end of the trial... those in the low-carb group on insulin were using less while those in the low-fat group were using more : "Of the participants on insulin, the dose was reduced by a mean (±SD) of 10±14 units in the low-carbohydrate arm and increased by 4 ±19 units in the low-fat arm (p=0.12) at 12 months."

[foxl]

But here is an interesting snippet which failed to make it to the conclusion... although the A1C was comparable in both groups at the end of the trial... those in the low-carb group on insulin were using less while those in the low-fat group were using more : "Of the participants on insulin, the dose was reduced by a mean (±SD) of 10±14 units in the low-carbohydrate arm and increased by 4 ±19 units in the low-fat arm (p=0.12) at 12 months."

And no discussion of the implications of THAT?

[fgummett]

And no discussion of the implications of THAT?They do mention it.. almost as a negative used to justify why the low-carb group had an initial greater weight loss "Additionally, low-carbohydrate arm participants had greater reduction in insulin dose and due to insulin’s potential effect on weight gain this reduction may have promoted a greater weight loss."

Can't they see this is a GOOD thing... to be encouraged!

I think it is laughable just how transparent the agenda is here -- whatever happened to impartial science that bases its conclusions on the findings, rather than the preconceptions :confused:

[foxl]

They do mention it.. almost as a negative used to justify why the low-carb group had an initial greater weight loss "Additionally, low-carbohydrate arm participants had greater reduction in insulin dose and due to insulin’s potential effect on weight gain this reduction may have promoted a greater weight loss."

Can't they see this is a GOOD thing... to be encouraged!

I think it is laughable just how transparent the agenda is here -- whatever happened to impartial science that bases its conclusions on the findings, rather than the preconceptions :confused:

Frank ... I think they are deliberately understating and it may go over SOME heads ... but not others? Just a guess though! I mean, they DID THE STUDY!

[REDLAN]

They do mention it.. almost as a negative used to justify why the low-carb group had an initial greater weight loss "Additionally, low-carbohydrate arm participants had greater reduction in insulin dose and due to insulin’s potential effect on weight gain this reduction may have promoted a greater weight loss."

Can't they see this is a GOOD thing... to be encouraged!

I think it is laughable just how transparent the agenda is here -- whatever happened to impartial science that bases its conclusions on the findings, rather than the preconceptions :confused:

Interesting post, and study. The result is not unexpected. The cochrane found similar results in type 2 when they compared low and high carb diets - i.e. little difference.

Improved HDL in low carb diets is not unexpected either - this result has been shown in other studies looking at low carb diets (not necessarily type 2 related). Low-carb diets can raise total cholesterol. Whether this has a significant effect on health outcomes (either raised cholesterol or improved HDL) is a somewhat moot point.

Now for the reduced insulin usage in low-carb diet. It is not discussed for one very simple reason, and that is....

p=0.12

the result is not statistically significant. The result could have occured by chance, ergo there is nothing to discuss, except perhaps designing a study with sufficient power to measure insulin usage.