Intense exercise before starting a fast can help you reach ketosis faster, research suggests

June 15, 2025

Gabby LandsverkDecember 3, 2021

• Intermittent fasting may help improve metabolism and prevent disease, according to research.
• Starting a fast by exercising could help you see the benefits more quickly, a new study suggests.
• An intense workout burns through stored energy, which helps you reach ketosis quicker, researchers theorize.

Intermittent fasting, the trend of abstaining from food for set periods of time in the day or week, is praised by some experts as an aid for weight loss and disease prevention.

You may be able to benefit even more from fasting if you kick start it with a workout, which could help you reach ketosis faster, according to a study published in the journal of Medicine & Science in Sports & Exercise

Researchers from Brigham Young University in Utah looked at 20 healthy men and women who completed two 36-hour fasting periods, one starting with exercise and one without. They were looking to see how quickly participants reached ketosis, a metabolic state of burning fat for energy. Ketosis occurs after the body runs out of carbohydrates or glucose, its preferred fuel source, either through fasting or a low carb diet.

The researchers determined whether participants were in ketosis by testing them for one specific type of ketone, a chemical the body produces during ketosis. The chemical, beta hydroxybutyrate (BHB), has been linked to health benefits like reduced inflammation, better blood sugar control, and lower risk of aging-related diseases.

Typically, it can take between 20 to 24 hours of fasting for ketosis to begin and ketones to appear. However, this study found that participants were in ketosis three and a half hours sooner, on average, when they started their fast with an exercise session.

Intense exercise may help quicken ketosis by burning off carbs

Researchers theorized that exercise helped kickstart the fast by using up some of the body’s glucose, or stored carbohydrate energy. Participants worked out by running on the treadmill for 40 to 50 minutes with intense effort (70% of their maximum heart rate). It’s not clear from this study what type of exercise might be ideal for inducing ketosis, or how long you need to work out for best results. The best exercise style and timing may also vary from person to person. Previous research has shown, though, that high-intensity exercise burns glucose more quickly.

“The more carbohydrates you burn off (without overdoing it or injuring yourself), the better you set the stage for starting ketosis early in your fast,” Landon Deru, lead author of the study and a PhD student at Brigham Young University, said in a press release.

Working out could also improve your mood while fasting

Some evidence suggests exercise can boost appetite, prompting you to eat back calories you’ve burned off, but this study found participants weren’t hungrier when fasting after a workout.

While fasting generally was linked to some unpleasant side effects, like hunger or moodiness, exercise didn’t seem to exacerbate them. In some cases, participants who worked out reported feeling happier during the fast, potentially because the brain releases feel-good chemicals during and after exercise (sometimes called a runner’s high).

“Everyone’s going to be a little grumpier when they fast, but we found that you aren’t going to feel worse with the intervention of exercise — with exercise, you can get these extra benefits and be the exact same amount of grumpy as you would be if you didn’t exercise,” Deru said.

Read the original article on Insider

5 Ways to Ditch Diet Culture

June 1, 2025

Dr. Erin Nitschke by Dr. Erin Nitschke
on September 16, 2022

Diet culture is a set of beliefs and practices that worship thinness and equates body size with health or morality. It is also the lens through which beauty is commonly viewed and defined. In other words, diet culture reflects socially prescribed standards based on whatever is considered “hot” or “perfect” at the time. The saddest aspect of diet culture is that it sets consumers up for failure and disappointment because, truthfully, the “perfect body” does not exist. If we continue to chase it, the only thing we will catch is frustration and a constant fear of not being “enough” as we are.

Shifting Standards

Much like the fashion industry, the “ideal” has shifted over time and throughout the decades. In the 1500’s, having more body fat did not carry the same stigma that it does today (this is seen throughout famous paintings in that era). Instead, it was once viewed as a sign of wealth and health. Further, depending on the era, women’s beauty standards evolved from voluptuous and curvy to hourglass to supermodel-esque bodies. Today, we see a greater focus on “ripped” physiques and lifting heavy weights.

This is not to say that men’s attractiveness standards have not also changed. In the 60’s and 70’s, a thinner physique was glamorized. Now, the “standard” is large and muscular. This is seen even in kids’ action figures – in the 80’s GI Joe was small-framed; in the early 2000’s, those same figures become much larger.

These standards along with pervasive diet culture lies are a source of constant external pressure that carries the message that we are not good enough. Instead, what we need understand that it is ok to want to make healthy changes to our bodies while accepting that there is nothing “wrong” with how we are currently. This is called body harmony.

Diet Culture Messages to Reject

Diet culture is not limited to the messages included in this article. However, what follows is a list of the most common diet culture lies that tend to throw us off track and have us questioning ourselves and our “enoughness”. Let’s examine these messages and how we can reframe our thoughts around these lies.

1.Bread is bad and causes weight gain if consumed. Bread is not bad. It is a staple in many meals. It is also an enjoyable food product and can offer quality nutrients (depending on fiber and micronutrient content). Bread, alone, will not cause weight gain directly. It is the overconsumption of calories that is the real cause of weight gain. Unless you have an allergy to bread, enjoy it as you like. For better blood sugar control, choose whole grain options and pair it with natural nut butter, cheese, or other protein and/or fat.

2.Sugar is evil. The message should be that an excess of sugar can be a cause for concern. If someone is consuming excess sugar throughout the day, this can cause dental issues, nutrient deficiency, and blood sugar control problems. It is perfectly acceptable to enjoy sugar in small quantities such as desserts and coffee or tea. 

3.Always eat clean. The first concern with this statement is the dichotomous thinking – that foods are either clean or dirty or good or bad. There’s no moral value with food. Food is food, it is fuel, and it is nourishment. The second concern is with the word “always”. It is not realistic for humans to always or never do something and carry that on in perpetuity with no “slips”. Lastly, there is no specific agreed upon definition of what “clean” is. Does it mean organic? Does it mean only whole foods, and nothing packaged? It is open to interpretation. Instead, the focus should be on adding more nutritious foods to the diet (fruits, leafy veggies, starchy veggies, and lean proteins) rather than taking away or eliminating foods. Food is not dirty or bad. Food is generally nutrient-rich or energy-dense. Sometimes, it is both.

4.Weight loss is healthy progress. When considered as a stand-alone metric, body weight is unhelpful and does not indicate health or disease. In fact, weight loss, if it is significant can be a sign of disease or dysfunction. To truly define health, we need to look at metrics like blood pressure, mineral storage, sleep fitness, stress levels, mental health, body composition, resting heart rate, body temperature, etc. Weight represents a person’s relationship with gravity, not their health.

5.Work out to burn calories or earn food. No one needs to earn their food. We are physical beings and by the nature of our existence, we need to consume food to even remain at maintenance body weight and health. The importance here is to be mindful of honoring hunger cues, staying within a reasonable caloric intake and enjoying regular physical movement and NEAT movement (Non-exercise activity thermogenesis, or the calories burned by the movements we make when we go about our daily business). Exercise is not a punishment for consuming dessert or a way to earn a slice of pizza. Food is not money to be exchanged for work. Eat. Move. Enjoy.

We will not likely eradiate diet culture or the insanity of its messages. What we can do is call them out and recognize them for what they are. Diet culture is about image and restriction. A valid, effective, and scientific approach to achieving optimal health is rooted in behavior change, patience, and finding a harmony between what the body needs and what you enjoy. Health and fitness is not about the body; it is about your relationship with your body. This is where our power is.

Author
Dr. Erin Nitschke
Contributor

Dr. Erin Nitschke, NFPT-CPT, NSCA-CPT, ACE Health Coach, Fitness Nutrition Specialist, Therapeutic Exercise Specialist, and Pn1 is a health and human performance college professor, fitness blogger, mother, and passionate fitness professional. She has been in the health and exercise industry since 2003. Erin believes in the power of a holistic approach to healthy living. She loves encouraging her clients and students to develop body harmony by teaching focused skill development and lifestyle balance. Erin is also the Director of Educational Partnerships & Programs for the NFPT. Erin is also an editorial author for IDEA and NFPT where she writes on topics related to personal training, health coaching, behavior change, and career success. Email her at erinmd03@gmail.com.