Dream Big: Intermittent Fast for One Week

Here’s your step by step plan to go from having never fasted before to fasting each day for seven days straight.

by Carmen Roberts, M.S., R.D., L.D.N. Health Professional, Medical Reviewer

Intermittent fasting (IF) isn’t just about shedding a few extra pounds. It’s an approach to eating that’s been shown to have positive, long-term effects for your overall health. But as beneficial as it can be, IF is also just as hard to stick to. That's where this four-week plan comes in. Not only will you find answers to all of your IF questions, but you'll also learn some of the science behind the eating approach and the steps to take if you're ready to incorporate IF into your life.

Week 1: Ease into Intermittent Fasting

The science: It’s the latest trend in the weight loss world: intermittent fasting (IF). And it’s not just hype. Research has shown that in addition to weight loss, it can reduce inflammation, improve blood sugar and lipid levels, and reduce blood pressure, even when your daily caloric intake stays the same. And, unlike most popular diets that focus on WHAT to eat, intermittent fasting is solely about WHEN to eat. This is an attractive option for people who don’t want to follow a meal plan or count calories.

There are several ways to approach IF. All guide you with regular time periods to eat and fast, but the most popular is the daily approach, which centers on eating during a six or eight-hour period and fasting for the remainder of the day.

Maybe you’re already sold on this approach to weight loss, and you’re eager to try it. Before you do, remember, IF isn’t for everyone. Ryan Andrews, a registered dietitian and adjunct instructor for SUNY in Purchase, NY, advises, “Intermittent fasting is discouraged for people who participate in high amounts of physical activity, women who are pregnant or breastfeeding, and people with a history of disordered eating.” People with diabetes or insulin issues also need to proceed with caution.

Reminder: IF is a meal-timing plan, not a license to eat whatever you want during non-fasting hours. So, put down the deep-fried chicken wings and the bag of chips. (We know. It hurts.) And let’s get started.

Move the Needle Monday: We’re here to walk you through, step by step over the course of four weeks, the best way to go from having never fasted before to fasting each day for seven days straight—establishing a habit that sets you up for better health. Andrews recommends starting slowly. “I like the idea of allowing a 12-hour gap between dinner and breakfast for most everyone. It's a healthy practice that offers little risk. If you are in the routine of eating dinner at 8 p.m. and breakfast at 6 a.m., try to eat dinner by 7 p.m. and breakfast at 7 a.m. This change alone offers a 12-hour gap between feedings and might be enough for your body to see the benefits.”

The plan: Start your week by choosing a 12-hour fasting time frame that works best for you. If you are an earlier riser and like to work out in the morning, waiting until 10 a.m. to eat may not be realistic. If you are a night-owl, you need to choose a 12-hour window that allows you to eat a later evening meal before you begin your fast.

To put it plainly: Once you’ve had your first meal of the day, take your last bite of food within the next 12 hours. The reverse is also true: Once you’ve had your last meal of the day, whether it’s a 6 p.m. or 9 p.m., wait 12 hours before eating anything the next day. The only beverages that are allowed during your fast are water, coffee, and tea. Calorie-free drinks, such as diet soda, or calorie-free foods made with artificial sweeteners (like sugar-free gum) are not allowed, since research is still mixed on the effect that these sweeteners have on digestion.

Top tip: Dragging in the morning? You ARE allowed to have black coffee or green tea before breaking your fast (and you’ll never think of the word break*fast in quite the same way), as long as you skip the cream and sugar, that is.

Week 2: Extend Your Fasting Window

The science: Intermittent fasting (IF) is not such a new concept. In fact, it’s an ancient one, even if fasting back in the Stone Age wasn’t intentional. Unlike humans today, our ancestors did not consume three large meals (plus snacks) each day, nor were they sedentary, since they had to farm, hunt, and gather for their food to survive. They were also focused more on going to sleep once it was dark in order to be rested enough to get up and gather more food the next day.

Chronic disease and obesity did not dominate the landscape. So, it makes sense that we should mimic the lifestyle of our ancestors to reduce our risk of disease. And, since it took hundreds of thousands of years for humans to evolve, we can’t expect our physiology to instantly adapt to our more modern lifestyle without there being a serious hiccup or two.

Bottom line: Reducing overall food intake (within reason) actually increases human lifespan, according to an IF study review published in The New England Journal of Medicine.

Move-the-Needle Monday: Your goal this week is to extend your fasting window by an additional two hours—meaning, you up your no-eating game from 12 hours to a full 14. Still not convinced that this simple change will help you lose weight? “Intermittent fasting seems to provide as much weight loss benefit as steady dieting does, while being easier to adhere to,” says Larry Cheskin, M.D., a professor of food and nutrition studies at George Mason University in Fairfax, VA. Research shows that giving your body an extended period of time without food makes your body exhaust its sugar stores and burn body fat, leading to weight loss.

The plan: Delay your breakfast for an additional hour and eat your dinner one hour earlier than you did last week. So, if you were fasting from 8 a.m. until 8 p.m. last week, your goal for this week should be to eat all of your meals between 9 a.m. and 7 p.m. This may be tricky if you get home from work late or plan on going to the gym in the evening, so you’ll need to prepare a plan to adjust your eating schedule accordingly. Consider packing nutrient-dense snacks like nuts, dried fruits, cheese, or protein bars when you travel to help you stay on track.

Top tip: If you’re feeling lightheaded, be sure to stay hydrated, since water loss also occurs with weight loss. (Makes sense, when you think about it, but it might not be the first thing that comes to mind during a fast.) You may also need to cut back on more intensive exercise until your body adjusts to its new schedule.

Also, take note of when you’re feeling hungry. Is it late at night? First thing in the morning? You might have to create some distractions to take your attention away from the fridge. Retire to bed an hour earlier, read a book, or sip on some unsweetened herbal tea at night to calm the hunger pangs.

Week 3: Eat Only During an 8-Hour Window

The science: Intermittent fasting (IF) isn’t just about shedding a few extra pounds. It’s an approach to eating that’s been shown to have positive, long-term effects for your overall health. “There are many potential benefits besides weight loss, including healthier blood lipids, blood sugar, blood pressure, inflammatory markers, and body composition. All of this can decrease our odds of developing chronic diseases like heart disease, cancer, and even dementia,” says Ryan Andrews, a registered dietitian and adjunct instructor for SUNY in Purchase, NY.

Move-the-Needle Monday: A smaller feeding window doesn’t mean that you should spend your available eating time gorging on anything you can get your hands on. Amy Allen-Chabot, Ph.D., a registered dietitian and professor of nutrition at Anne Arundel Community College in Arnold, MD, warns, “My concern is that people who adopt a 16:8 hour fast-to-feeding schedule think they can eat anything they want during the hours they can eat. Fasting for 16 hours is not a license to eat junk food for the other eight hours.” Long-term research shows that a diet rich in whole grains, fresh fruits and vegetables, low-fat dairy products, and healthy fats found in fish, nuts, and olive oil is still the most recommended style of eating for health and disease prevention, so focus on eating quality foods when you do break your fast.

The plan: Your goal this week is to eat only three meals—and no snacks—during an eight-hour time period. Sound impossible? This will involve more planning on your part. If you’re working in an office for eight hours, you will need to pack most (if not all) of your meals. Consider delaying your breakfast until 10 a.m., breaking for lunch at about 2 p.m., and eating dinner before you leave the office at 5:30 p.m., so that your fasting can begin by 6 p.m. sharp.

Top tips: If you are still struggling with hunger at this point, rest assured that it will subside over time as your body adjusts to your new schedule. Most experts agree that it takes about two to three weeks for your body’s hunger pangs during a fasting period to subside. Drink several glasses of water in the morning while fasting, or sip on decaf coffee in the evening to help keep hunger at bay. Take a brisk morning walk or evening stroll to take your mind off all the goodies in the cupboards and the fridge.

Week 4: Eliminate the Morning Meal Altogether

The science: If you needed another reason to continue with your intermittent fasting (IF) goals, consider this: Caloric restriction alone has been shown to help to prevent a whole host of ills, including obesity, diabetes, hypertension, oxidative stress, cancer, and cardiovascular disease, according to multiple studies. Research also shows that IF appears to guard against several age-related conditions, including neurodegenerative disorders, such as Alzheimer’s disease. And, periods of IF can result in improved learning ability and memory, too. All the reason to see this thing through to the finish line: mastering the 18-hour fast.

Move-the-Needle Monday: You’ve made it this far—now what? If you’ve fully adjusted to the last fasting period, you’re ready to move to the next level: consuming all your meals within a six-hour period, then fasting for the remaining 18. For most, this means eliminating the morning meal altogether and moving to a pattern that includes two substantial meals and a healthy snack in between.

The plan: For best results, eat your lunch at noon, a snack at 2:30 p.m., and dinner at 5:30 p.m. For lunch, choose a combination of protein and carbs when you break your fast (like a wrap with turkey and cheese, or a veggie pizza). Snack time is the best time of day to eat more carbohydrate-rich foods like cereal with milk or yogurt and fruit. Since carbs are digested more quickly, this will help you still feel hungry at dinner. At dinnertime, choose protein-rich foods and foods that contain heart-healthy unsaturated fats to help you feel fuller for longer at night, when most people start to feel hungry again. A grilled salmon salad topped with nuts and avocado, or a tofu stir fry made with veggies and olive oil are both good choices. Drink low-fat milk between meals if you’re feeling too full at mealtime.

Sound impossible? Ryan Andrews, a registered dietitian and adjunct instructor for SUNY in Purchase, NY, advises, “With nutrition, a level of individualization is required. For some, strict IF works very well for their physiology, body rhythms, schedule, and lifestyle. For others, not so much. So, don't feel like strict IF is mandatory for improving health and body composition.” That means if you can’t realistically stick to this limited of an eating window each day, consider trying the alternate day fasting approach (also called the 5:2 approach). This allows you to eat regularly for five days each week while limiting yourself to just one 500- to 600-calorie meal on the remaining two days. Research shows that the 5:2 method can be equally effective as the daily approach for both weight loss and cardiovascular risk reduction.

Top tips: Well done! You’ve made it to week 4 and a full week of intermittent fasting! Even if you couldn’t quite make it over the 16:8 finish line, practicing any type of time-limited eating has benefits. Your body has likely adjusted to this new way of eating, but if you don’t think that you can sustain this approach every day, consider trying it just a few days each week.

Larry Cheskin, M.D., a professor of food and nutrition studies at George Mason University in Fairfax, VA, who has studied IF and its effect on weight loss, says, “The trick is to provide a time-controlled break from eating, while maintaining an overall reduced calorie intake.” Meaning, research shows that any method of IF, even if it’s not every day, will lead to some weight loss. And you’ll still achieve some health benefits even if you can’t stick to a strict fasting and feeding schedule every day of the week.

Carmen Roberts, M.S., R.D., L.D.N.
Meet Our Writer
Carmen Roberts, M.S., R.D., L.D.N.

Carmen is a Registered Dietitian. In addition to writing for HealthCentral, she has spent her career working at Johns Hopkins and is also an adjunct faculty instructor for Excelsior College. Carmen has over 20 years of experience in nutritional counseling, education, writing, and program management and is a certified specialist in adult weight management. She enjoys educating her students and clients about how nutrition affects the body and its role in overall health and wellness.