While intermittent fasting isn’t a new concept, it has become increasingly popular over the last decade. Individuals are taking on the challenge of restrictive eating for the benefits of longevity and weight loss. Unfortunately, the obesity epidemic in the United States continues to grow each year due to bad eating habits and lack of physical activity.
Always consult your doctor before starting a nutrition program like intermittent fasting to ensure that it’s safe for you and won’t interfere with any conditions or medications.
There are several different levels of intermittent fasting, including 10:14, 12:12, and 16:8. Many individuals start with longer eating windows and cut down over time as their body adjusts to restriction.
While you must get enough calories and nutrients during your eating window, don’t overconsume excessive calories, as your body will take longer to get to the stored fat if it’s still burning new calories.
This only leads to a higher risk of diabetes, heart disease, and other serious illnesses. Let's explore how intermittent fasting can quickly help reverse these health risks — with advice from experts like Dr. Peter Attia who have devoted their careers to helping individuals improve longevity.
Dr. Peter Attia and the three golden rules
Peter Attia, MD, is the founder of Early Medical and a leading voice in the health and wellness world. With a focus on applying the principles of Medicine 3.0, Peter has dedicated himself to understanding the best ways to improve the health and lifespan of his clients. His expertise spans various topics, including nutritional interventions, exercise and sleep physiology, mental health, and pharmacology.
Dr. Attia’s diet can be divided into three golden rules:
- Time restricted feeding. This is a type of intermittent fasting.
- Avoid sugars. High fructose corn syrup and junk food ingredients can easily be found in many processed foods but are often hidden in foods that you wouldn’t deem unhealthy, — including salad dressings and other sauces. It’s crucial to check the labels to avoid these kinds of ingredients.
- No restriction on healthy starches and vegetables. These foods often contain many nutrients our body needs, such as fiber, calcium, and B vitamins.
Time restricted eating
Let’s start with the first and foremost rule: time-restricted feeding. This is a type of intermittent fasting. Attia fasts between 14–16 hours each day at the low end and between 20–22 hours at the high end. Attia only time-restricts his eating 4–5 days a week.
Attia uses a parameters' scenario to explain the restriction of dieting and nutrition in a simplified manner. Within this “pulling three levers” scenario, he discusses:
- What you eat (dietary restriction or DR)
- How much you eat (caloric restriction or CR)
- When you eat and don’t eat (time restriction or TR)
While adjusting to a fasting restriction, you can start with a smaller fasting window, such as 10:14 — restricting for 10 hours and eating within a 14-hour period. Once your body adjusts, you can increase your restriction window to 12:12, 10:14, and 18:6. Eventually, you will end up fasting for around 18 hours per day while eating your daily calories in a 6-hour window.
"One thing is for certain: if you want to be sick, don’t do any of these things — eat as much as you want (no CR), of anything you want (no DR), whenever you want (no TR). This is called the 'standard American diet.' The further you can get away from this pattern of eating, the better. As I say in the video, always pull one of the levers; often pull two; sometimes pull all three."Peter Attia, MD
The physician’s blunt statement makes us all rethink our current diets and what we can do to improve them — if we want the longevity Attia has been working so hard to spread to his clients and audience over the last several years.
Benefits of intermittent fasting:
Here are some benefit of intermittent fasting:
- Hormonal and cellular. When you fast, your hormone levels begin to adapt, making your stored body fat more accessible for burning. It also initiates the cellular repair process, autophagy — removing waste products from your cells.
- Promotes weight loss. Intermittent fasting prolongs the period after your body has burned through the calories you have eaten and begins burning fat. In addition, human growth hormone (HGH) levels increase, promoting fat-burning and muscle gain. For example, 59 participated in an 8-week study to see hunger and weight changes. After alternate-day fasting for 8 weeks, researchers saw reductions in fat mass, fat-free mass, visceral fat mass, and resting metabolic rate. Fasting leptin and insulin also decreased. Regarding hunger, it did not show an increase, but fullness did increase.
- Decreases your risk for diabetes. Alternating fasting days can reduce your body’s resistance to insulin, which helps control the amount of sugar in your blood.
- Improves heart health. Intermittent fasting is highly beneficial for those with heart conditions or heart-related conditions, including blood pressure, triglycerides, bad cholesterol.
- Good for the brain. Changes in your metabolic function improve during a fasting state and can improve memory, oxidative stress, and even resistance to injury and disease.
Foods groups to focus on during intermittent fasting
- Protein (chicken, salmon, pork, lean meat)
- Carbohydrates (rice, potato, sweet potato)
Who should not try intermittent fasting
- Women who are pregnant or breastfeeding.
- Individuals with type 1 diabetes who are taking insulin (there are concerns about unsafe levels of hypoglycemia during fasting).
- Those with a history of eating disorders.
Time-restricted feeding or intermittent fasting has many benefits beyond maintaining or losing weight. Studies show it can improve longevity and overall wellness. In addition, excess fat and obesity are associated with almost every disease, from insulin resistance to cancer to Alzheimer’s. When we lose fat, the risk of these diseases also vastly reduces.
Attia recommends focusing on the metabolic benefits that improve with intermittent fasting — if your goal is to lose weight, it will come along with it. But, before you start intermittent fasting, you should talk to your doctor to ensure it’s safe for you.
- Peter Attia MD. My Nutritional Framework.
- UCLA Health. Health Benefits of Intermittent Fasting and Tips for Making it Work.
- Clinical Nutrition. Changes in Hunger and Fullness in Relation to Gut Peptides Before and After 8 weeks of Alternate Day Fasting.
- Harvard Health Publishing. Intermittent Fasting: The Positive News Continues.
- MDPI Nutrients. Effects of Intermittent Fasting on Brain Metabolism.