Calories are the currency of weight management and any weight loss diet has to offer fewer calories than the body needs.
However, the means by which this caloric deficit is best achieved remains an area of continuing debate. While the proponents of ketogenic low-carb diets cite the greater ease of lowering weight, proponents of low-fat diets extol the putatively greater benefits on lipid profiles.
Nevertheless, previous studies have clearly shown that in the end both strategies lead to the same amount of weight loss, even if the low-carb approach may initially seem more effective.
This observation is once again confirmed in a new study by William Yancy Jr and colleagues from the Veterans Affairs Medical Centre, Durham, NC, published in the latest issue of the Archives of Internal Medicine.
In this study 146 overweight or obese outpatients (mean age 52 yrs) were randomized to either a ketogenic low-cab diet (initially <20 g of carbohydrate daily) or the lipase inhibitor orlistat (120 mg TID) combined with a low-fat diet (<30% energy from fat, 500-1000 kcal/d deficit) over 48 weeks.
Of the initial participants, 79% completed the low-carb arm whereas 88% completed the orlistat plus low-fat diet. Weight loss was similar between the groups, with participants losing around 9% of their initial body weight on either diet.
While the low-carb diet appeared to have a more beneficial impact on blood pressure, the orlistat low-fat combination appeared to have a greater beneficial impact on LDL-cholesterol.
However, in the end it is probably fair to say that both approaches led to more or less similar improvements in body weight and related risk measures, showing once again that this is probably not so much about which diet is more effective as it is about which diet works best for you.
Thus, in clinical practice it is likely that some patients will find it easier and preferable to severely restrict their carb intake, while others may find it easier to reduce their calories from fat by taking orlistat and reducing the fat in their diet.
The bottom line in both case is that the benefits will only persist as long as the participants stay on their respective diets or treatments. This makes it even more critical that patients chose the strategy that works best for them and that they are most likely to stay on in the long term.
Remember, neither diet is likely to “cure” obesity. As with all obesity treatments, when the interventions stop the weight comes back.
AMS
Edmonton
In The News
February 1st, 2010 at 9:12 am
I’m guessing you’ve probably come across Christopher Gardner’s JAMA article comparing atkins, ornish, learn, and the zone?
http://jama.ama-assn.org/cgi/content/full/297/9/969
He finds the lower carb diet to be beneficial in the short term wrt weight loss and bio-markers (tho it is really a moderate carb diet at 12 months).
But have you seen his presentation? It’s on YouTube, and here’s a PDF of his slides for one he did at a conference:
http://www.dphhs.mt.gov/PHSD/cardiovascular/pdf/Gardner_presBattle_of_the_Diets_FINAL08Summit.pdf
Check out slides 40-42. He makes an interesting case for the benefits of a lower carb diet for women who are insulin resistant, but a lower fat diet for those who are insulin sensitive.
February 1st, 2010 at 1:06 pm
You can in effect lose weight without decreasing calories if you increase oxygen capacity and utilization.