Ask an R.D.: What’s the 80/20 Rule for Weight Loss, and Does Diet Matter More than Exercise?By Carole Anderson Lucia Reviewed by Briana Rodriquez, RDN Science-Backed
You may have heard of the 80/20 rule as it relates to many different things, from business (the idea that 20 percent of workers contribute 80 percent of results) to efficiency (the concept that 80 percent of results come from 20 percent of the effort). But have you heard of the 80/20 rule as it relates to diet and exercise?
The premise is relatively simple: To lose weight, you need to consume fewer calories than your body uses as energy. And while common wisdom used to say that exercise is the best way to create such a calorie deficit, research indicates that while physical activity is a necessary component of weight loss, cutting calories through your diet is much more achievable — and necessary.1
In a nutshell, the 80/20 rule for weight loss says you should aim to cut 80 percent of your calories through diet and burn 20 percent through exercise.
We spoke with Jenny Craig’s Registered Dietitian, Briana Rodriquez, R.D., to find out more about the 80/20 rule. She shares why eating a healthy, reduced-calorie diet is the mainstay of weight loss — and how getting regular exercise can help support your weight loss … and help maintain it.
Why diet should be your focus when it comes to weight loss
According to Rodriquez, eating a healthy, well-rounded diet is important not just for your overall health, but for weight loss as well. And while exercise is also important for your health in a number of ways — from reducing your risk of various diseases such as diabetes and metabolic syndrome; to strengthening your bones and muscles; to improving your mental health and mood2 — it can be difficult to get enough exercise to create the calorie deficit necessary for weight loss without changing your diet.
For instance, a man who weighs 154 pounds and is 5’10” will burn approximately 280 calories by walking at a moderate pace for one hour, according to the United States Department of Agriculture.3 If he did vigorous exercise, such as running, for one hour, he would burn 590 calories.
Since it’s estimated that a pound of fat is equivalent to 3,500 calories, the average person needs to reduce their caloric intake by approximately 500-1000 calories a day in order to achieve a healthy weight loss of 1-2 pounds a week.4
"Reaching that deficit through exercise alone would be difficult for many — if not most — people,” Rodriquez says. If, on the other hand, you were to skip out on eating 1 cup of ice cream, you would save approximately 273 calories. Swap a chicken drumstick for chicken breast and you can cut about 80 calories.5 If you do the math, you’ll see that you can reach that all-important calorie deficit more easily by focusing on your diet — while using exercise to support your efforts.
The quality of your diet matters
As important as it is for your overall health, regular exercise cannot make up for a poor-quality diet. In fact, Americans are exercising more than ever, yet the rates of obesity are rising sharply.
In 1997, for example, approximately 44 percent of U.S. adults met the 2008 federal guidelines for aerobic activity (at least 150 minutes per week of moderate-intensity or 75 minutes of vigorous-intensity exercise); as of 2017, 53.8 percent did. Yet during the same timeframe, the rates of obesity among U.S. adults rose by 12 percent: from 19.4 percent in 1997 to 31.4 percent in 2017.6
At the same time, the standard American diet has suffered in quality and has become a major factor in our obesity crisis, studies have shown.7 Consider the following statistics:
- About 37 percent of Americans ate fast food on any given day between 2013-2016.8
- In the United States, on any given day, half of all people consume sugary drinks. Of those, 25 percent get at least 200 calories from such drinks, while 5 percent get at least 567 calories from them.9
- Only one out of every 10 U.S. adults eats enough fruits or vegetables.10
- In 2010, the average American took in about 23 percent more calories per day — 2,481 — than in 1970.11
And the most alarming statistic: Today, more than 70 percent of U.S. adults are overweight or obese.12
Yet Americans aren’t the only ones whose diets have suffered over the years. Researchers have found that in many countries, the rates of obesity have tripled or quadrupled over the past 30 years — at the same time that these nations’ diets have transitioned to high-calorie, highly processed fare.7
How exercise can help your efforts
Always consult your physician before starting a new exercise program.
Remember: The 80/20 rule doesn’t rule out exercise; it says that it should support your weight-loss efforts. Here’s how it can help:
1. Exercise can help you over a plateau. As you lose weight and fat, you might also lose a bit of muscle mass, which may slow your metabolism, leading to a plateau. If you’ve been working out steadily for about 30 minutes a day regularly, try bumping up your exercise intensity and duration to help get you back into weight loss mode. Adding strength training can also help, as it will add more muscle, which in turn will burn more calories.13 Research shows that strength training also increases fat loss, especially when combined with diet modifications and aerobic exercise.1 And it can help keep you from gaining dangerous belly fat.14
2. Exercise helps with weight maintenance. In fact, observational studies suggest it is crucial.1 Researchers from the Mayo Clinic suggest that an exercise program that is reasonable and achievable (30 to 60 minutes of exercise five to seven days per week, for instance) is critical for long-term weight maintenance.
Tips for healthy weight loss
In addition to watching portion sizes and calorie counts, Rodriquez recommends the following strategies to help support your weight loss goals:
1. Aim to get exercise on most days. Federal guidelines15 recommend that all people get 150 minutes of moderate to vigorous physical activity per week (30 minutes, five days per week, for instance). For weight loss purposes, more exercise — up to 60 minutes per day — may be necessary. In addition, the Centers for Disease Control and Prevention16 recommends that adults do muscle-strengthening exercises involving all major muscle groups at least two days per week.
2. Limit certain foods. The Harvard School of Public Health17 recommends limiting or avoiding the following foods, which have been linked to obesity:
- Fruit juices (even if they are 100 percent fruit juice, they can have as much sugar and as many calories as sugary sodas).
- Processed meats (like hot dogs or deli meat).
- Refined carbohydrates.
- Sugary drinks (like soda and energy drinks).
- Sweets (like candy).
3. Focus on a well-rounded diet. To promote health and weight loss, the Centers for Disease Control and Prevention18 suggests the following:
- Eat plenty of fat-free or low-fat dairy products, fruits, vegetables and whole grains.
- Include lean meats in your diet, including beans, eggs, fish, nuts and poultry.
- Keep your diet low in added sugars, cholesterol, saturated fats, sodium and trans fats.
Remember, a combination approach — focusing on your diet and incorporating exercise — has been found to be the most effective way to lose weight. We hope you’ll use this information to structure a healthy, achievable path to weight loss.
Jenny Craig follows expert guidelines to create delicious, nutritionally balanced meals that support your weight loss goals. And if you need help with motivation, tools or other information, Jenny Craig is here to help with a balanced approach to a healthy lifestyle. Get started on your path to better health and wellness with a free appointment today!
Carole Anderson Lucia
Carole is an award-winning journalist based in Southern California who specializes in health and wellness topics. Her work has appeared in Parents, Fit Pregnancy, Mom & Baby, Yahoo News, Viv magazine and Lifescript. She's won several national awards for her work including a National Science Award and two National Health Information awards. A frequent contributor to Jenny Craig’s Blog, Healthy Habits, she enjoys gardening, spending time at the beach and adopting far too many rescue animals in her spare time.
Favorite healthy snack: jicama dipped in homemade hummus.
Reviewed by: Briana Rodriquez, RDN
Briana is a Registered Dietitian Nutritionist and Certified Personal Trainer for Jenny Craig, based in Carlsbad, California. She is passionate about utilizing food as functional and preventative medicine. Guided by a simplistic and optimistic approach, Briana’s philosophy is to help people improve their health and achieve their goals through the development of sustainable habits to live a healthy life. In her free time, you can find her strength training, indoor cycling, coffee tasting, and at local eateries with her husband and two dogs.
Favorite healthy snack: peanut butter with celery alongside a grapefruit-flavored sparkling water (so refreshing!).
This article is based on scientific research and/or other scientific articles and is written by experienced health and lifestyle contributors and fact-checked by Briana Rodriquez, RDN, Registered Dietitian Nutritionist at Jenny Craig.
Our goal at Jenny Craig is to provide the most up-to-date and objective information on health-related topics, so our readers can make informed decisions based on factual content. All articles undergo an extensive review process, and depending on topic, are reviewed by a Registered Dietitian Nutritionist (RDN) or Nutritionist, to ensure accuracy.
This article contains trusted sources including scientific, peer-reviewed papers. All references are hyperlinked at the end of the article to take readers directly to the source.