Which Diet Is Best for Weight Loss?

One day, calories are the enemy. The next day, it’s carbs. No wonder people are confused about the best way to shed unhealthy extra pounds. Internal medicine specialist Crystal Lantz-DeGeorge, MD, offers insight into what really works.

Q: Are some diets better than others in helping people lose weight?

A: There are two ways to lose weight – to restrict calories or to restrict carbohydrates. All diets are a variation on either of these two principles. The best diet for an individual is the one that they will follow.

Some people prefer counting calories and others will not follow a restricted-calorie diet and prefer a low-carbohydrate diet. Others prefer not to count, measure or weigh anything, and these are people who would do better on a meal-replacement diet using prepackaged food items from a variety of different companies.

However, there is clear scientific evidence that eating carbohydrates (sugars and starches) causes insulin levels to rise in everyone. Insulin signals the body to store carbohydrate as fat and triggers hunger. When patients are consuming a high level of carbohydrates in any diet, it is very difficult for them to lose body fat and weight loss is slow and inefficient.

Q: What does research say about the effectiveness of different diets?

A: Studies have compared low-fat diets (which are always low-calorie), low-carbohydrate diets (consuming anywhere from 20 grams to 100 grams of carbohydrate per day only) and the Mediterranean diet (1,500 calories per day for women and 1,800 calories per day for men with no more than 35 percent of calories from fat with fat mainly coming from olive oil and nuts).

We have found that across the board, patients on a low-carbohydrate or Mediterranean diet lose more weight than those on a low-fat diet though people still lose weight on a low-fat diet if that is their preference.

The low-carbohydrate diet has the best effect on raising HDL, or good cholesterol, and lowering triglycerides. A Mediterranean diet has the most favorable effect on LDL or bad cholesterol, and both the Mediterranean diet and low-carbohydrate diet do the best job improving blood sugar control, which means they treat diabetes or prevent prediabetes from turning into diabetes.

Q: How do you advise people to go about the challenging task of losing weight?

A: Since it is very clear that insulin is a strong signal for making and storing fat, and eating fewer carbohydrates prevents insulin surges that not only trigger fat storage but also hunger, I tend to advocate low-carbohydrate diets for patients.

At the beginning of the diet, this may mean eating very low levels of carbohydrates, but over time we increase the grams of carbohydrates a patient eats and their diet looks more “normal” to them. However, I have patients who do much better with calorie restriction and those who have been most successful on meal-replacement diets.

I tell patients that weight loss, no matter how it is achieved, is a long process and having the support and accountability a physician provides can be very helpful. Diet changes are the major force that drives weight loss, but physical activity is a must in maintaining weight loss.

Additionally, there are several Food and Drug Administration-approved medications that can modestly assist in weight loss if diet and exercise alone aren’t effective. Finally, bariatric surgery can be a lifesaving procedure in the appropriate patient who has a significant amount of weight to lose.

Crystal Lantz-DeGeorge, MD, is an internal medicine specialist and hospitalist at UH Suburban Health Center Physicians.