News & Events

Added to My Toolbox
Removed from My Toolbox
Added to My Toolbox
Removed from My Toolbox
Apr 18, 2018

Low-Fat and Low-Carb Diets are Equally as Effective, Study Finds

Experts advise selecting an eating plan based on what works for you and what you can maintain over time.


When it comes to losing weight, it doesn’t matter which type of diet you choose as long as you stick to it, based on a one-year comparison of low-fat versus low-carb diets.

Published in the Journal of the American Medical Association, this study compared weight loss with low-fat versus low-carb diets. It also looked at the impact of genetics on success with one diet over another.

The results, however, suggest that both diets work equally as well—regardless of our DNA.

Conducted by researchers at Stanford University, this study included 609 overweight or obese adults from the San Francisco Bay area. Through the study, participants were randomly assigned to either a low-carb or low-fat diet for one year. During this period, they attended regular classes where they received dietary instructions and support from certified dieticians.

For the first two months, participants limited their intake of fat or carbohydrates to 20 grams a day, depending on their assigned diet. They then slowly added fat or carbs back into their diet, while keeping fat or carb consumption as low as they could maintain.

All participants were also encouraged to stay active and maintain a healthy diet throughout the study.

After one year, researchers found no significant difference in weight loss between either groups. Average weight loss was 12 pounds in the low-fat group and 13 pounds in the low-carb group.

Researchers also found that genes had no impact on weight loss in either group. Studies have identified three genes—PPARG, ADRB2 and FABP2—that could make individuals more responsive to either low-fat or low-carb diets. However, these genetic patterns had no impact on weight loss with either diet in this study.

Researchers also found no association between participants’ insulin levels and weight loss with either diet, despite evidence linking the two.

What findings show, according to authors, is that there’s no clear winner between low-carb and low-fat diets. Both are just as effective and can help people lose weight, especially when coupled with a healthy lifestyle. Findings also suggest that DNA doesn’t explain why certain individuals do better on one type of diet compared to another. What’s more important, according to authors, is that people find a diet that works for them and can be maintained over time.

Questions for You to Consider

  • What is a healthy weight for me?
  • A few important tools can be used to determine if an individual is underweight, normal weight or overweight. The easiest tool is a Body Mass Index, which is calculated using height and weight to estimate levels of body fat. However, Body Mass Index is not always accurate, particularly among individuals with extremely high or low amounts of muscle. In these cases, measuring waist circumference is helpful in assessing weight, as a waist circumference greater than 35 inches for a woman or 40 inches for a man is considered unhealthy.
  • What is the best way to lose weight?

  • Weight loss boils down to a simple formula: burn more energy each day than you take in from food. A deficit of 3500 calories will net one pound of fat loss. Therefore, if you cut down your food intake by just 100 calories a day, you can expect to lose 10 pounds by the end of the year.

    Although it’s tempting to look for a quick fix with a speedy weight loss scheme, many popular diets are unhealthy or produce only temporary results. You’ll have better luck with an eating plan that includes a variety of healthful foods and gives you enough calories and nutrients to meet your body’s needs. Taking it slow by making ongoing eating and exercise changes is the best way to reach and maintain your optimal weight.

Infographic: Obesity

Related

Tailored Weight Loss Intervention

The more weight loss programming available, the better equipped we are to combat obesity.

What We Eat May be Key to Weight Maintenance

These days, it’s hard to know what foods we should eat to stay healthy and maintain a healthy weight.

Obesity Rates Stabilizing, Reports Show

Obesity rates have stabilized nationally but have increased in certain populations since the late '90s.

Balancing What and How Much We Eat

The Choose My Plate food guidelines help balance the amount and types of food we eat.

Is Weight Loss Surgery Safe and Effective?

Weight loss surgery helps patients keep weight off and reduce heart disease risk.

Do You Have 'Sitting Disease'?

Most of us sit for more than half of our waking hours. Researchers say that is too much. Learn more »

Eat Better

healthy eating

Healthy eating is an important part of healthy living. Learn more »