Time-restricted feeding works in four steps. Talk to your doctor about your conditions and medications. Stop sugars, artificial sweeteners, processed foods and vegetable oils. Build meals on protein and healthy fats. Then start with an 8-hour eating window and narrow it by about one hour a week.
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What is time-restricted feeding?
Time-restricted feeding can help people move into a healthier lifestyle. It can help reverse insulin resistance and keep a healthy weight. Most people eat from the time they wake up until the time they go to bed. Typically, they eat three main meals, many snacks, and often soda in between. This pattern leads to chronic high insulin production, which wears out the insulin receptors. Also, insulin is a fat storage hormone. High insulin levels lead to fat building up in the liver, which creates metabolic inflammation.
Your metabolism has two states: the “fed” (insulin high) state and the “fasted” (insulin low) state. Either we are storing food energy (adding to storage), or we are burning stored energy (shrinking storage, or fat lysis). Say we start eating the minute we roll out of bed and do not stop until we go to sleep. Then we spend almost all our time in the fed state. Over time, we gain weight, because we have not given our body time to burn stored food energy.
Time-restricted feeding shortens the time window when a patient eats. That shortens the “fed” state and lengthens the “fasted” state. This lowers the total amount of insulin made in a day. Insulin is a fat-storage hormone, and a high level of insulin production leads to insulin resistance. Time-restricted feeding is a type of fasting. It has extraordinary benefits, including weight and body fat loss, and lower blood insulin and sugar levels. It also brings a reversal of type 2 diabetes. Other possible benefits include clearer thinking and focus, and a lower risk of Alzheimer’s disease. It may also turn on cellular cleansing by stimulating autophagy, and reduce inflammation.
Time-restricted feeding is a type of fasting. It is not starvation. Starvation is the involuntary absence of food for a long time. It leads to severe suffering or even death. Starvation is not planned or controlled. Fasting is choosing not to eat. It is done by someone who is not underweight, so they have enough stored body fat to live off. When done right, intermittent fasting should not cause suffering. Food is easy to get, but you choose not to eat it. You may begin a fast at any time you choose, and you may end it at will, too. You can start or stop a fast for any reason or no reason at all. Any time that you are not eating, you are intermittently fasting. For example, you may fast between dinner and breakfast the next day. That is about 12-14 hours. In that sense, intermittent fasting should be seen as part of everyday life.
Just having insulin present increases fat storage. When insulin is absent, the body can use lipolysis, or burning fat as energy.
Lifestyle changes are key to managing obesity and Type 2 Diabetes. But by themselves they don’t always control blood glucose levels. Bariatric surgery (gastric band or bypass) works but has significant risk. Drugs often manage the symptoms and may stave off complications, but they don’t reverse the disease.
Time-restricted feeding has the potential to fill this gap in obesity and diabetes care. It provides calorie restriction and the hormonal benefits of bariatric surgery, without invasive surgery. Time-restricted feeding means the controlled and voluntary choice to skip all food and drinks with calories for a set period of time. During the fasting periods, patients may drink unlimited amounts of very-low-calorie fluids. These include water, coffee, tea, and even bone broth. A general multivitamin is encouraged to provide enough micronutrients.
Metabolic flexibility:
Time-restricted feeding, or meal-timing strategy, reduces swings in hunger. It changes how the body burns fat and carbs, which may help with losing weight and improving insulin sensitivity. It does not necessarily change how many total calories patients burn. But it reduces the daily hunger swings and increases fat burning at night. It improves metabolic flexibility, which is the body’s ability to switch between burning carbs and burning fats. Metabolic flexibility is how easily the body moves between two opposite states, “fed” and “fasted,” without cravings or hunger pangs.
During feeding, insulin is high, which tells your body to store extra calories as fat. When insulin is present, fat burning stops, and the body burns glucose instead. In the fasted state, insulin is low, while glucagon and growth hormone rise. So the body pulls stored body fat from your fat cells and burns this fat for energy (instead of glucose). You can only burn stored body fat while in the fasted state. And you can only store more body fat while in the fed state.
Most overweight patients live in a constant fed state, and rarely in a fasted state. Their cells keep burning glucose rather than fat. They have insulin resistance, caused by chronically high insulin levels. These high levels promote fat storage and block fat from being released.
Overweight “sugar burners” may stop eating for even a few hours. When they do, they quickly run out of glucose from their last meal, instead of moving to the fasted state and burning stored body fat. This causes acute brain signals of hunger and cravings for sugar right away. They spend most of the day trapped in a cycle. They eat every few hours, spike glucose, and then get hungry when blood sugar drops. They may even get low blood sugar and feel jittery. This is called reactive hypoglycemia. It is a big clue that a patient lacks metabolic flexibility.
Fat-adapted energy use:
Your metabolic flexibility is set by your mitochondria, the tiny energy factories inside the cells. The mitochondria can burn either glucose (sugar) or fat for fuel. Over time they will prefer one over the other. “Sugar burners” have built up the pathways in the mitochondria that burn glucose and decreased the pathways for burning fat. As you become more metabolically flexible, the fat burning pathways will take over, and you will become “fat adapted.”
Becoming fat adapted takes time and practice. Your body has to do a number of things to slowly up-regulate (or increase) your fat-burning pathways. It must improve insulin sensitivity to lower insulin and help release fat as free fatty acids. It must also upregulate the fat-burning pathways at the cellular level (in the mitochondria).
Ways to improve fat adaptation include:
- Low-carbohydrate diets: A low-carb, high-fat (LCHF) diet helps the body use fat for energy rather than glucose. That is because there is more fat and less glucose, even in the fed state.
- Exercise: High-intensity exercise uses up glucose and glycogen fast. This forces the body to switch to fat for fuel. Exercise also improves insulin sensitivity.
- Caloric restriction: Eating fewer calories also means less glucose for fuel. This forces the body to rely on stored body fat for fuel.
- Intermittent fasting makes the body spend more time in the fasted state. This gives the body more “practice” at burning fat.
- Supplementation: Ketone supplements may be useful when first starting out. Ketones are breakdown products of fat. When you first start out, ketones can reduce your hunger and give energy to your mitochondria.
Patient education and engagement is the key to remission and to cutting back on drugs. Morrison et al. also found that more frequent contact with a provider led to markedly rapid drops in serum glucose, HbA1C, and low-density lipoprotein cholesterol levels. This was in patients who followed up with the treating physician on average every 2 weeks.
How to do time-restricted feeding:
Our protocol can reverse obesity and Type 2 Diabetes in people who can still make some insulin. It does this by resensitizing the insulin receptor and restoring normal cyclical insulin production. We restore the normal ebb and flow of insulin, so the receptors are re-sensitized. The constant high level of insulin in the blood drops, which reduces insulin’s fat storage action.
Time-restricted feeding is a type of intermittent fasting. It limits your eating to a certain number of hours each day. Here is an example. You choose to eat all your food for the day in an 8-hour period, such as from 11 a.m. to 7 p.m. That gives an 8-hour feeding window. The other 16 hours are the fasting period, when you eat no calories. You repeat the same schedule every day.
Limit feed times to a shorter window each day. Start at 8 hours/day and reduce by 1 hour per week down to 4-6 hours/day. This is highly effective in reversing diabetes and producing weight loss. Medications must be adjusted by a clinician to prevent glucose levels that drop too low by accident, or changes in blood pressure. These can be life-threatening. To succeed with this technique, prevent cravings. Feeling full is the key. You should not be hungry, or this will not last. Food choice drives feeling full.
Steps to success
Step 1
Before you start a time-restricted feeding schedule, talk to your doctor or health care provider. Get medical advice from a professional who shares your health goals.
You may have medical conditions that need close monitoring. You may also be on medications that may need to be adjusted. Before you start a fasting program, it is important to understand your medical history and the medications you take. Please talk to your doctor or healthcare provider.
Step 2
Stop all sugars, including all artificial sweeteners. Many sugars and processed carbs just don’t fill you up. Stop all sugar and artificially sweetened drinks. Before you start your protocol, remove sugars and processed carbohydrates.
Stop all sources of vegetable oil. Replace them with healthy natural oil and real butter. Swapping industrial seed oil for real oils is easy if you are not eating processed foods. It even makes the food taste better.
Stop all processed foods. Processed foods are built to make you eat again and again and again, every 2-3 hours.
Step 3
Focus on protein and healthy fats. Choose meals that are rich in protein and healthy fats. Eat all types of meat like beef, fish, chicken, eggs, lamb, and seafood. Yogurt and cheeses are also nutritious and filling. Fill up on low-sugar vegetables like olives, peppers, cucumbers, and avocado. Eat as many green leafy vegetables as you please. This helps your body adapt to burning fat and may make fasting easier to start.
Step 4
Start slow. This metainflammation didn’t happen in one day, and it won’t go away in a day. Try a generous 8-hour eating window on your first day to see how it feels. Eat as you please during your 8-hour time frame. Then see how your body and appetite feel for the rest of the day.
Then, slowly narrow your eating window. As you get better at judging your hunger and understanding hunger pangs, you can slowly shrink your daily feeding window. Try cutting by one hour a week, until you reach a 4-hour window.
Things to think about:
You may notice hunger pangs if you haven’t first changed your diet to include more filling foods. These are foods full of protein, healthy fat and fiber. If you have hunger pangs, try drinking some hot tea, coffee, water or seltzer. This will fill your stomach up. It gives you enough time to realize that maybe you really aren’t as hungry as you first thought. Some people use lemon in seltzer water.
This should be a fun experience, not a miserable one. If you are miserable, something has been overlooked. Remember that time-restricted feeding is a great way to limit snacking. Eating filling real food during your eating window will restore and realign your hormone system.
Patients can reverse their diseases without worrying about the side effects and cost of many pharmaceuticals. They also avoid the unknown long-term risks and uncertainty of surgery. They do it all by means of time-restricted feeding.
Some practical tips:
- Don’t use time-restricted feeding as an excuse to eat junk food when you are eating. Keep avoiding processed foods.
- When you first start time-restricted feeding, you might have to use a fast-mimicking substance like a ketone supplement.
- Check with your doctor before starting time-restricted feeding, especially if you are diabetic and on diabetes medications!
- You can generally take any vitamins or supplements you want while fasting, as long as they don’t have calories. But you don’t need any supplements, because you will be eating plenty of nutrient-dense foods every day. You may have to eat more salt.
- You don’t have to worry about losing muscle from lack of protein during your fast. Just eat enough protein at the meals before and after fasting. An LCHF (low-carb, high-fat) diet pairs nicely with intermittent fasting, as both improve fat adaptation a great deal.
- You can exercise with time-restricted feeding, either cardio or lifting weights. Lifting weights is better. You will not lose muscle while fasting as long as you exercise regularly.
- Drink plenty of water and non-caloric drinks while fasting. Coffee and tea in the morning make fasting much more enjoyable. They also bring health and fat-burning benefits, and are highly recommended.
- Skipping your morning meal gives your body more time to burn fat for energy. Hunger is lowest in the morning, so it may be easiest to skip it and break your fast later in the day.
Time-restricted feeding has many benefits but remains controversial. Diabetes medications will need to be adjusted. Discuss any changes in medication and related lifestyle changes with your doctor. Some people should not use time-restricted feeding. These include those who are underweight or have eating disorders, pregnant or breastfeeding women, and children under the age of 18.
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Frequently asked questions
Is time-restricted feeding the same as intermittent fasting?
Time-restricted feeding is one type of intermittent fasting. It limits all food to a set number of hours each day and repeats the same schedule daily. Intermittent fasting is the broader term. Any time you are not eating, you are fasting, such as the 12 to 14 hours between dinner and the next breakfast. Fasting is voluntary, and it is not starvation.
What are the best hours for time-restricted eating?
A common start is an 8-hour window, such as 11 a.m. to 7 p.m., with a 16-hour fast. Skipping the morning meal works well. That is because hunger is lowest in the morning, and it gives your body more time to burn fat. From there, shorten the window by one hour a week until you reach 4 to 6 hours a day.
What are common mistakes with 16:8 fasting?
The big one is using the eating window as an excuse to eat junk food. Keep avoiding processed foods. Skipping protein and healthy fats leaves you with hunger pangs. Starting without your doctor adjusting diabetes or blood pressure medication can be life-threatening. Forgetting water and non-caloric drinks also makes fasting harder. So does not adding salt when you need it.
What should you eat during your eating window?
Build your meals on protein and healthy fats. Eat all types of meat, including beef, fish, chicken, lamb and seafood, plus eggs. Yogurt and cheese are nutritious and filling. Add low-sugar vegetables like olives, peppers, cucumbers and avocado. Eat as many green leafy vegetables as you like. This helps your body adapt to burning fat, which makes fasting easier.
How many hours should your eating window be?
Start with a generous 8-hour eating window. Eat as you please during those 8 hours. Notice how your body and appetite feel for the rest of the day. As you get used to hunger, shrink the window by about one hour a week until you reach a 4-hour window. Go slow: the metainflammation did not happen in a day.
What can you drink during the hours you are not eating?
Hot tea, coffee, water and seltzer all help when hunger pangs hit. They fill your stomach and give you time to notice that you may not be as hungry as you first thought. Some people add lemon to their seltzer. Leave out sugar-sweetened drinks and artificial sweeteners. They have no place in this plan.
Additional references:
Sutton EF, Beyl R, Early KS, et al. Early time-restricted feeding improves insulin sensitivity, blood pressure, and oxidative stress even without weight loss in men with prediabetes. Cell Metabolism. 2018. PMID 29754952
Suleiman Furmli, Rami Elmasry, Megan Ramos, Jason Fung. Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin. BMJ Case Reports, 2018; bcr-2017-221854 DOI: 10.1136/bcr-2017-221854
Morrison F , Shubina M , Turchin A . Encounter frequency and serum glucose level, blood pressure, and cholesterol level control in patients with diabetes mellitus. Arch Intern Med 2011;171:1542–50.doi:10.1001/archinternmed.2011.400
Duke S-AS , Colagiuri S , Colagiuri R . Cochrane Metabolic and Endocrine Disorders Group. Individual patient education for people with type 2 diabetes mellitus. Cochrane Database Syst Rev 2009;22.doi:10.1002/14651858.CD005268.pub2
Brethauer SA , Aminian A , Romero-Talamás H , et al . Can diabetes be surgically cured? Long-term metabolic effects of bariatric surgery in obese patients with type 2 diabetes mellitus. Ann Surg 2013;258:1.doi:10.1097/SLA.0b013e3182a5034b
Pucher PH , Lord AC , Sodergren MH , et al . Reversal to normal anatomy after failed gastric bypass: systematic review of indications, techniques, and outcomes. Surg Obes Relat Dis 2016;12:1351–6.doi:10.1016/j.soard.2016.01.030
Shoar S , Nguyen T , Ona MA , et al . Roux-en-Y gastric bypass reversal: a systematic review. Surg Obes Relat Dis 2016;12:1366–72.doi:10.1016/j.soard.2016.02.023
The University of Alabama at Birmingham. “Time-restricted feeding study shows promise in helping people shed body fat.” ScienceDaily. ScienceDaily, 6 January 2017. www.sciencedaily.com/releases/2017/01/170106113820.htm
Intermittent versus daily calorie restriction: which diet regimen is more effective for weight loss? K. A. Varady. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-789X.2011.00873.x
Moro, T., Tinsley, G., Bianco, A., Marcolin, G., Pacelli, Q. F., Battaglia, G., … Paoli, A. (2016). Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. Journal of translational medicine, 14(1), 290. doi:10.1186/s12967-016-1044-0. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5064803/
Gabel, K., Hoddy, K. K., Haggerty, N., Song, J., Kroeger, C. M., Trepanowski, J. F., … Varady, K. A. (2018). Effects of 8-hour time restricted feeding on body weight and metabolic disease risk factors in obese adults: A pilot study. Nutrition and healthy aging, 4(4), 345–353. doi:10.3233/NHA-170036. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6004924/
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Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP
Interventional pain physician, addiction medicine specialist and obesity medicine diplomate.
Licensed in Missouri and Illinois.
Last reviewed June 17, 2026
