There are numerous diet plans out there, all touting to be the best. Some are better than others but how do you decipher this information? Lists that rank and discuss pros and cons of the most common commercial diets are available and always subject to the authors’ biases. Beyond all the marketing of slender figures there are some less sexy, black and white documents found in the databases of PubMed that have looked at this clinical question objectively.
Background 101: How to dissect a commercial diet for weight loss.
- By the ratio of fat, protein and carbohydrate. Let’s call this Macronutrient proportions.
- By the amount of caloric restriction.
- By its impact on health risk factors.
In order to dissect a diet plan you need to assess it for these 3 main characteristics. First, understanding the recommended proportions of macronutrients, is it low carb, low fat/high carb or some other perfect mix. Secondly, understand the caloric restriction expected. What was this number based upon; will exercise be encouraged or discouraged? Thirdly, what are the beneficial or detrimental side effects this diet will so generously provide. Is weight loss the bottom-line or are things like life expectancy worth taking a look at too.
Numéro un: Macronutrient proportions head to head
- Low carb diet: The low-carbohydrate, non–restricted-calorie diet was based on the Atkin’s Diet
- High carb/low fat diet: The low-fat, restricted-calorie diet was based on the American Heart Association guidelines.
- Mediterranean diet: The moderate-fat, restricted-calorie, Mediterranean diet is rich in vegetables and low in red meat, with poultry and fish replacing beef and lamb.
The major difference in most diets are the way in which they may emphasize or de-emphasizes certain macronutrient groups. To analyze the diet you want to embark on you must understand their rational, if any, for they’re magical weight loss secret.
When these 3 diets were put head to head in a controlled study setting here were the results. The fastest amount of weight loss occurred in the first six months of this 2-year trial for all diet types. At six months the low-carb diet (Atkin’s) showed the most significant weight loss. At the end of the trial, 2 years later, the Mediterranean diet and the Atkin’s diet demonstrated equal average weight loss of 4.4kg and 4.5kg respectively. These results highlighting that despite Atkin’s initial greater weight loss at 6 months these were not sustained and greater regain was found within the 2 years. The low fat-diet demonstrated inferior weight loss throughout the 2-year period with an average 2.9kg of weight loss (Trichopoulou et al., 2007).
Another well-designed 2-year study echoed similar results:
“Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize (Sacks et al., 2009).”
Bottom line: Short-term Atkin’s does appear to have greater weight loss success that is quickly overshadowed by a faster regain in the following months. In the long-term, the Mediterranean and the Atkin’s diet seem equivocal as far as weight loss is concerned.
Numéro deux: Caloric restriction head to head
- Very low cal diet: <800 kcal/day ie. HCG Diet, fasting, liquid diets
- Low cal diet: 800-1350 kcal/day ie. Dr Bernstein, weight watcher’s
Do you want the quickest way to weight loss? You may have found it. At less than 800 calories a day you might as well call it a prolonged fast. At the end of 6 months the very low calorie diet lost 16.1 % of their body weight in comparison to 9.7% for the low calorie diet groups (Tsai and Wadden, 2006).
Yes, there it is. If you are looking for a quick short-term solution this may be your best bet. If you are looking for long-term success, not so much. The individuals in the very low calorie diet were the quickest to regain the weight and no difference in weight was seen between the low cal diet and the very low cal diet at 1 year.
At the end of the day it appears compliance and caloric restriction are greater determinants to long-term weight loss than macronutrient composition of the diet.
Feel free to check out the references here.
Unimpressed with the study results so far? I know the results are far from exciting and definitely less interesting than the models plastered in the diet advertisements. My next article will discuss numéro trois, selecting a diet based on its impact on health risk factors among other things.
What has your experience been on commercial diet? Care to share some pros and cons?
Image credit: Rob Owen-Wahl