If you’re looking to maintain your weight this holiday season, then follow a diet that is high in protein, moderate in fat and limited in simple carbs.

This advice is based on a large European study that found adults following this type of diet had a lower dropout rate and continued to lose weight during the 6-month weight maintenance phase following a two month weight loss program. The study results were published in a recent issue of the New England Journal of Medicine.

Diet, Obesity, and Genes (Diogenes) is the world’s largest dietary intervention study that looked at the efficacy of moderate fat diets that vary in protein content and glycemic index (GI) for preventing weight regain and obesity related factors after weight loss.

"Those in the high-protein groups and low glycemic groups were two to three times more likely to achieve additional weight loss during the maintenance phase than those in the low protein and high glycemic groups."

The study had two legs – a weight loss program and a weight maintenance program. Almost 800 overweight adults (mean BMI of 34) from eight European countries completed the 8-week weight loss program. The median age of study participants was 41, who weighed almost 200 pounds and had 36 percent body fat.

After losing at least 8% of their baseline weight during the first phase of the study, participants were randomly assigned to one of five maintenance diets for 26 weeks:

- Low protein and low glycemic index
- Low protein and high glycemic index
- High protein and low glycemic index
- High protein and high glycemic index
- Control group following a diet with moderate protein content and no specific recommendations for glycemic index

The low protein diets consisted of 13 percent of total energy intake whereas the high protein diets consisted of 25 percent of total energy intake. Low GI diets were 15 glycemic index units lower than the high GI diets.

The five diets were designed to have a moderate fat intake of 25 to 30 percent of total calories. There were no restrictions on daily caloric intake (ad libitum diet) to test the ability of the diet to regulate appetite and body weight.

Although 773 participants entered the weight maintenance phase of the program, just 548 or 71% completed the intervention. The drop out rate was lower in groups assigned to high protein or low glycemic index diets. Almost 40 percent of participants in the low protein, high glycemic index group dropped out of the study compared with about a quarter of those in the other groups.

During the study, the average weight regain was only about one pound. However, weight gain was about 2 pounds higher in the low protein and high-glycemic groups vs. the high protein and low-glycemic index groups. Participants in the low protein, high GI diet groups had significant weight gain of almost 4 pounds. This compared to a weight loss of about 1 pound in the high protein, low GI index group.

Importantly, those in the high-protein groups and low glycemic groups were two to three times more likely to achieve additional weight loss during this phase than those in the low protein and high glycemic groups.

While the diets of study participants were carefully controlled, researchers estimated that the actual difference in protein intake was 5.4 percentage points between the high protein and low protein groups (vs. goal of 12 points) and 4.7 glycemic index units between the low glycemic index and high glycemic index groups (vs. goal of 15 units).

Even those the protein and GI targets were not met, study authors were encouraged by the results. “The results indicate that even a modest reduction in glycemic-index values was sufficient to minimize weight regain and promote further weight loss in obese patients after a successful weight-loss diet. Higher dietary adherence might have resulted in even greater weight loss.”

A second part of this study involved the children of the overweight participants. They were not required to participate but to just follow the same diet as their parents. Almost half of the children in these families were overweight. For the children who maintained a high-protein, low glycemic index diet, like their parents, the prevalence of obesity dropped by 15 percent (from 46% to 39%). These study results were published separately in the American Journal of Pediatrics.

The Bottom Line

One of the biggest challenges of any weight loss program is keeping the weight off long-term. Studies have repeatedly demonstrated that most diets fail. This is due to a combination of factors but feeling hungry is a big issue for many dieters.

The current study reveals that a high protein, low glycemic index diet helps dieters maintain their weight loss and even assist in long-term weight loss. A reason for this success may be that this style of eating is much easier to stick with than a diet imposing severe restrictions. High protein diets also seem to quell hunger and that promotes long-term success.

How can you incorporate this type of diet into your life? By featuring lean protein and complex carbs at every meal. Here’s some ideas:

Breakfast: Have a bowl of fruit with non-fat, plain Greek yogurt instead of a bagel, cereal or muffin.

Mid-Morning Snack: Select a hard boiled egg instead of a bag of chips.

Lunch: Opt for a small salad with turkey, chicken, fish or other lean meat instead of a sandwich.

Late Afternoon Snack: Select an apple with a handful of walnuts instead of a cookie or candy bar.

Appetizer: Nosh on raw celery, carrots, or jicama and dip in hummus or tabouleh instead of cheese and crackers.

Dinner: Prepare two vegetables (e.g., asparagus and squash) along with protein (e.g., grilled chicken) instead of pasta.

Dessert: Treat yourself to a bowl of berries and a tiny piece of dark chocolate instead of a bowl of ice-cream.

For more information about glycemic index and glycemic load, refer to From Simple Carbs to Slow Carbs.