Diet Type or Calories Lost: What's Best for Weight Loss?

By Margaret Furtado, M.S., R.D.

A 2009 study published in The New England Journal of Medicine examined longer-term dieting, and asked what was more important for losing weight: the composition of the diet (that is, the proportions of fat vs. protein) or caloric intake.

The study

Subjects (811 men and women) were randomly assigned to one of these 4 diets, all of which totaled at least 1,200 calories:

•low fat/average protein
•low fat/high protein
•high fat/average protein
•high fat/high protein
The participants were encouraged to exercise at least 90 minutes a day and they received counseling every 8 weeks over the 2-year period. Group sessions were provided 3 out of 4 weeks in the first 6-month period and 2 out of 4 weeks the remaining 18 months of the study.

The results

Regardless of which diet the subjects were on, their weight loss and decreases in waist circumference were the same for all 4 groups. Overall, the participants lost an average of 13 pounds the first 6 months and kept 9 pounds off after 2 years. The greatest weight loss was seen in the first 6 months, and all groups exhibited slow weight regain starting at 12 months. As a group, they all showed improvements in LDL (bad) cholesterol, triglyceride, and insulin levels.

Bottom line

As long as your diet is balanced and healthy overall, you can lose weight and keep a good amount of it off if you watch the calories. The researchers thought it significant that those who attended at least 2/3 of the counseling sessions lost an average of 22 pounds, compared to the participants who didn't get counseling and lost an average of 9 pounds overall.

Cut calories inch by inch

Here are some ways to cut calories that won't leave you hungry:

•skim milk instead of creamer in your coffee (2 creamers = 45 calories; skim milk = negligible calories; plus, it adds calcium)
•butter spray instead of a pat of butter on your potato or bread (45 calories)
•1% milk instead of whole (50 calories)
•low-cal wheat bread instead of regular (~ 40 calories)
Even these little calorie-cutting adjustments can add up a lot.

Save 9 pounds effortlessly--over 2 years

Let's say you did nothing else differently in your diet plan or exercise routine except for making 1 of the 45-calorie changes above. (Yes, just 1!) Since 3,500 calories equals about 1 pound of weight, over the course of 2 years (the length of the study above), you could, in theory, lose 9 pounds.

Don't believe it? Here's the math:

•If you saved about 45 calories per day for 2 years (730 days), that would be: 730 x 45 = 32,850 calories saved over 2 years.
•The total number of "saved" calories (32,850) divided by the number of calories in 1 pound of weight (3,500) would be: 32,850/3,500 = 9.4, or about 9 pounds over 2 years!
Coincidentally, 9 pounds is what the subjects in this study lost, on average. Just think what you could do if you upped your physical activity, incorporated 3 of the calorie-cutting schemes above (3 x 45 = 135 calories saved per day), and started your own weight-loss support group!

To sum up

If you keep your diet low-fat overall (say, no more than 1/3 of calories from fat) and stay away from a lot of simple sugars, there are many versions of a healthy diet. Just don't overload on protein or protein supplements if you don't need them, since your body is going to treat them like surplus calories and convert them to fat.