Intermittent fasting has become a popular approach to healthy eating, with countless success stories paving its way into the mainstream. But while many people understand the importance of intermittent fasting and weight loss, tracking macros is another crucial aspect of the approach that can help you reach your goals even faster.
What are macros and micros? you ask? In short, macros (or macronutrients) are the protein, carbohydrates, and fats in your food, while micros (or micronutrients) are the vitamins and minerals that help support your bodily functions. The beauty of intermittent fasting is that it can be tailored to your unique lifestyle and goals. Pairing it with a focus on macros can help you achieve your goals even faster. This guide will explore intermittent fasting and macros to help you quickly count calories and reach your goals. DietAI's solution, the AI calorie counter, can take the guesswork out of calorie counting, making it easy to hit your macro targets every time you fast.
Table of Contents
Benefits of Intermittent Fasting for Weight Loss
Hormonal and Cellular Changes During Fasting
When you refrain from eating for a while, your body undergoes several changes. For example, it alters hormone levels to make stored body fat more accessible. It also begins crucial cellular repair processes. Here are some of the changes that may occur in your body as a result of fasting:
Insulin level
Your blood level of insulin drops significantly, which promotes fat burning.
Human growth hormone (HGH) level
Your blood level of HGH may increase dramatically. Higher levels of this hormone promote fat burning and muscle gain and have numerous other benefits.
Cellular repair
Your body starts crucial cellular repair processes, such as removing cell waste.
Gene expression
Beneficial changes occur in several genes and molecules related to longevity and protection against disease. Many of intermittent fasting's benefits are related to these changes in hormones, cellular function, and gene expression.
Intermittent Fasting for Weight Loss
Many people try intermittent fasting to lose weight. Generally, intermittent fasting will make you eat fewer meals. You'll take in fewer calories unless you compensate by eating much more during the other meals. Additionally, intermittent fasting enhances hormone function to promote weight loss. Lower insulin levels, higher HGH levels, and increased levels of norepinephrine all increase the breakdown of body fat and make it easier for your body to use fat for energy. For this reason, short-term fasting improves your metabolism, helping you burn even more calories. In a 2022 study involving 131 people with obesity, researchers found that those who participated in 12 weeks of intermittent fasting lost an average of 9% of their body weight, more than those who engaged in other weight loss methods. However, this study focused on the 5:2 intermittent fasting plan, which means the participants usually ate for 5 days and restricted their calories for 2 days each week.
The authors of a 2020 review of 27 studies noted that intermittent fasting participants lost 0.8–13% of their baseline body weight. In a 2020 trial, researchers focused on people who followed the 16:8 method, which involves fasting for 16 hours per day and eating within an 8-hour window. The people who fasted didn’t lose significantly more weight than those who ate three meals daily. However, after testing a subset of the participants in person, the researchers found that those who fasted had lost a significant amount of lean mass, including lean muscle. More studies are needed to investigate the effect of fasting on muscle loss. But, all things considered, intermittent fasting has the potential to be a powerful weight loss tool.
Reducing Insulin Resistance and Lowering Risk for Type 2 Diabetes
Intermittent fasting has been shown to significantly reduce insulin resistance and lead to an impressive reduction in blood sugar levels. Anything that reduces insulin resistance should help lower blood sugar levels and protect against type 2 diabetes. In a 2022 review of 10 studies on intermittent fasting, the authors concluded that fasting blood sugar was reduced by an average of 0.15 millimoles per liter in people with obesity and diabetes. A 2018 study in mice with diabetes also showed that intermittent fasting improved survival rates and protected against diabetic retinopathy, a diabetes complication that can lead to blindness. These results suggest that intermittent fasting may be highly protective for people who are at risk of developing type 2 diabetes.
Reducing Oxidative Stress and Inflammation
Oxidative stress is one factor that can contribute to aging and many chronic diseases. It involves unstable molecules called free radicals, which react with other essential molecules, such as protein and DNA, and damage them. According to a 2018 review, intermittent fasting may enhance your body’s resistance to oxidative stress. Additionally, a 2019 study suggests intermittent fasting can help fight inflammation, another key driver of many common diseases.
Intermittent Fasting and Heart Health
Heart disease is currently the world’s top cause of death. Various health markers, known as risk factors, are associated with an increased or decreased risk of heart disease. Intermittent fasting has been shown to improve several risk factors for heart disease, including:
blood sugar levels
blood pressure
blood triglycerides
total and LDL (bad) cholesterol
inflammatory markers
Cellular Repair Processes Induced By Fasting
When you fast, your body's cells start a process of cellular waste removal called autophagy. In this process, the cells break down and metabolize broken and dysfunctional proteins that build up inside them over time. Increased autophagy may protect against several diseases, including cancer and neurodegenerative diseases like Alzheimer’s.
Cancer Prevention
Cancer involves the uncontrolled growth of cells. Fasting has been shown to have several beneficial effects on metabolism that may reduce cancer risk. Evidence from animal studies suggests that intermittent fasting or diets that mimic fasting may help prevent cancer. However, human research has had inconsistent findings, and more research is needed to help health experts understand how intermittent fasting might affect cancer risk. There’s also some evidence that fasting may reduce the side effects of chemotherapy in some cases.
Brain Benefits of Intermittent Fasting
What’s good for your body is often good for your brain. Intermittent fasting improves various metabolic features known to be essential for brain health. Intermittent fasting can help reduce:
oxidative stress
inflammation
blood sugar levels
insulin resistance
Animal research has shown that intermittent fasting may increase the growth of new nerve cells, which could benefit brain function. Fasting also increases brain hormone levels, which are called brain-derived neurotrophic factor (BDNF). A BDNF deficiency may be involved in depression and other brain conditions. Additionally, animal research suggests that intermittent fasting may help protect against brain damage due to stroke. More research is needed in humans.
Alzheimer’s Disease and Intermittent Fasting
Alzheimer’s disease is the world’s most common neurodegenerative disease. There’s currently no cure for Alzheimer’s, so preventing it from developing in the first place is critical. Based on animal studies, the authors of a 2023 review hypothesized that intermittent fasting may delay the onset or reduce the severity of Alzheimer’s disease. However, this remains theoretical and unproven in humans. Animal studies also suggest that fasting may protect against other neurodegenerative diseases, including Parkinson’s disease and Huntington’s disease. However, more research in humans is needed.
Longevity and Fasting
One of the most exciting applications of intermittent fasting may be its potential to extend life span. Research in rodents has shown that intermittent fasting extends life span to continuous calorie restriction. Daily fasting has also been shown to improve the overall health of male mice. In a 2019 study, it helped delay the onset of conditions such as fatty liver disease and hepatocellular carcinoma, both common in aging mice. While researchers have not yet determined that fasting has the same effect in humans, intermittent fasting has become very popular in anti-aging circles. Given the known benefits for metabolism and all sorts of health markers, intermittent fasting could help you live a longer and healthier life.
How to Do Intermittent Fasting Effectively
Use DietAI to Count Calories While Fasting
Tracking your calorie and macro intake during intermittent fasting can help you stay on track and reach your dietary goals. DietAI transforms calorie counting with our AI calorie-counting app. Take a picture of your food, and our app instantly analyzes your meals from a simple photo, delivering accurate calorie and macro information without manual logging. Beyond photo recognition, the app provides comprehensive progress tracking, personalized nutrition insights tailored to your goals, and convenient barcode scanning for packaged foods. Whether trying to lose weight, gain muscle, or simply maintain a balanced diet, DietAI makes nutrition tracking effortless by eliminating the tedious aspects of traditional food journaling. Download now to effortlessly track your calories and macros with DietAI, the AI-powered app that makes logging meals as simple as snapping a photo. Download today for 80% off!
Fasting for 12 hours a day
The rules for this diet are simple. A person must decide on and adhere to a 12-hour fasting window daily. According to some researchers, fasting for 12 to 14 hours can cause the body to turn its fat stores into energy, which releases ketones into the bloodstream. This should encourage weight loss. This type of intermittent fasting plan may be a suitable option for beginners. This is because the fasting window is relatively small, much of the fasting occurs during sleep, and the person can consume the same number of calories daily. The easiest way to follow the 12-hour fast is to include the sleep period in the fasting window. For example, a person could choose to fast between 7pm and 7am They would need to finish their evening meal before 7 p.m. and wait until 7 a.m. to eat breakfast, but would be asleep for much of the time in between.
Fasting for 16 hours
Fasting for 16 hours daily, leaving an 8-hour eating window, is called the 16:8 method or the Leangains diet. Some experts may recommend females fast for 14 hours and slowly build their way up to 16 hours, while males can start fasting for 16 hours straight away. This intermittent fast may be helpful for someone who has already tried the 12-hour fast but did not experience any benefits. On this fast, people usually finish their evening meal by 8pm and skip breakfast the next day, not eating again until noon. A 2022 review found that this fasting method, alongside calorie restriction, may be beneficial for weight management in adults with overweight or obesity and may have a positive effect on blood sugar processing.
Fasting for 2 days a week
People following the 5:2 diet eat standard amounts of healthful food for 5 days and reduce calorie intake on the other 2 days. During the 2 fasting days, men generally consume 600 calories and women 500 calories. Typically, people separate their fasting days in the week. For example, they may fast on a Monday and Thursday and eat regularly on the other days. There should be at least 1 nonfasting day between fasting days. There is limited research on the 5:2 diet, which is also known as the Fast diet.
A 2022 study examining different types of fasting found that the 5:2 diet had no clear ranking compared to the other intermittent fasting regimens. A 2021 randomized controlled trial found that adults with obesity who tried the 5:2 fasting method with group support experienced a more significant weight loss at 6 weeks and rated the diet highly. However, the effect of weight loss diminished over time, with the weight difference no longer being significant by 1 year.
Alternate day fasting
There are several variations of the alternate-day fasting plan, which involves fasting every other day. For some people, alternate-day fasting means avoiding solid foods on fasting days, while others allow up to 500 calories. On feeding days, people often eat as much as they want. Alternate-day fasting is an extreme form of intermittent fasting, and it may not be suitable for beginners or those with certain medical conditions. It may also be difficult to maintain this type of fasting in the long term.
A weekly 24-hour fast
Fasting completely for 1 or 2 days a week, known as the Eat-Stop-Eat diet, involves eating no food for 24 hours. Many people fast from breakfast to breakfast or lunch to lunch. People following this diet plan can have water, tea, and other calorie-free drinks during fasting. People should return to regular eating patterns on non-fasting days. Eating this way reduces a person's total calorie intake but does not limit the specific foods the individual consumes. A 24-hour fast can be challenging and cause fatigue, headaches, or irritability. Many people find these effects less extreme over time as their bodies adjust to this new eating pattern. People may benefit from trying a 12-hour or 16-hour fast before transitioning to the 24-hour fast.
The Warrior Diet
The Warrior Diet is a relatively extreme form of intermittent fasting. It involves eating very little, usually just a few servings of raw fruit and vegetables, during a 20-hour fasting window, then eating one large meal at night. The eating window is usually only around 4 hours. This form of fasting may be best for people who have tried other forms of intermittent fasting already. Supporters of the Warrior Diet claim that humans are natural nocturnal eaters and that eating at night allows the body to gain nutrients in line with its circadian rhythms.
During the 4-hour eating phase, people should consume plenty of vegetables, proteins, and healthy fats. They should also include some carbohydrates. Although it is possible to eat some foods during fasting, it can be challenging to stick to strict guidelines on when and what to eat in the long term. Some people may also have difficulty eating such a large meal so close to bedtime. There is also a risk that people on this diet will not eat enough nutrients, such as fiber. This can increase the risk of cancer and harm digestive and immune health.
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Intermittent Fasting and Macros Tracking Together
If you practice intermittent fasting, macros are essential because they ensure that your body receives the nutrients for optimal health, energy, and performance during eating windows. Protein supports muscle repair and growth, which is crucial for maintaining lean body mass, especially if you're exercising while fasting. Carbohydrates provide energy for workouts and sustain overall energy levels while providing a source of fiber that will contribute to feelings of satiety. Carb quality is critical here if fat burning is your goal. At the start and end of your fast, you will want to avoid highly processed carbohydrates and added sugars because they can spike your blood sugar and insulin, thus reducing the fat-burning benefits of fasting.
Instead, choose high-fiber, minimally processed carbohydrates, such as non-starchy vegetables, nuts, dairy, and legumes. Fats play a role in hormone production, satiety, and absorption of fat-soluble vitamins. Healthy fats provide energy that does not spike your blood sugar, meaning insulin levels remain low, which can increase your chances of fat burning and weight loss. Balancing macros appropriately can help you meet your nutritional needs, support your fitness goals, and maintain overall well-being while practicing intermittent fasting.
Tracking and Adjusting Your Macros: How to Stay on Track
Once you start tracking your macros regularly, you can adjust them depending on your health goals. If your goal is weight loss, focus on protein first to minimize the weight loss from muscle mass loss. A higher protein intake of about 1.6-2.2 g/kg of body weight is a good place to start. Your carbohydrate and fat intake will make up the remaining calories. As long as you are generally healthy, the distribution of carbohydrates and fats shouldn't matter as much.
A landmark study published in the Journal of the American Medical Association (JAMA) found that weight loss was equivalent in the low-fat and low-carbohydrate groups as long as diet quality was high — meaning if your carbohydrates and fats are coming from minimally processed foods high in fiber and micronutrients and low in added sugars and processed oils, you should see similar weight-loss results.
Therefore, what percentage of your diet comes from carbohydrates and what percentage comes from healthy fats is up to personal preference and what you feel best consuming. Those with diabetes, heart disease, and other conditions may need a more directed approach to their protein, carbohydrate, and/or fat distribution. If you fall within these categories, work with a registered dietitian or healthcare provider to determine the ratio best for your unique condition.
Pay attention to portion sizes and stay within your macro targets for carbohydrates, protein, and fats. Monitor your progress regularly, and adjust your macros based on how your body responds. If you're not seeing results, consider adjusting your calorie intake or macro ratios slightly. Be patient and make gradual changes to avoid drastic swings in diet. Aim for consistency as you stick to your macro targets, eat nutrient-dense foods, and prioritize regular exercise to support your goals.
Balanced Macros for Intermittent Fasting: What Are the Right Ratios?
For intermittent fasting, a balanced macro ratio can range from 25-35% protein, 30-50% carbohydrates, and 25-35% fats. However, depending on your goals, consider a different approach, such as a lower-carb, higher-fat ratio for weight loss or a higher-carb intake for endurance athletes.
Here's a more detailed breakdown
Protein: 25-35% of total calories. Protein is crucial for muscle repair and maintaining satiety during the fasting periods.
Carbohydrates: 30-50% of total calories. Carbohydrates provide energy, especially during the eating window.
Fats: 25-35% of total calories.
Fats contribute to satiety, support hormone function, and can be a primary energy source, especially in low-carb approaches. DietAI transforms calorie counting with our AI calorie-counting app. Take a picture of your food, and our app instantly analyzes your meals from a simple photo, delivering accurate calorie and macro information without manual logging. Beyond photo recognition, the app provides comprehensive progress tracking, personalized nutrition insights tailored to your goals, and convenient barcode scanning for packaged foods. Whether trying to lose weight, gain muscle, or simply maintain a balanced diet, DietAI makes nutrition tracking effortless by eliminating the tedious aspects of traditional food journaling. Download now to effortlessly track your calories and macros with DietAI, the AI-powered app that makes logging meals as simple as snapping a photo. Download today for 80% off!
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What to Avoid While Intermittent Fasting
Slow Down and Ease Into Intermittent Fasting
Going from eating several meals a day to fasting for hours at a time can shock your system, so it makes sense to ease into intermittent fasting instead of jumping in head first. “Skipping breakfast, then lunch, and by 3 p.m., you’re willing to eat your arm,” says Libby Mills, M.S., RDN, owner of Libby Mills Nutrition. “If you normally eat every three to four hours and then suddenly shrink your eating period to an eight-hour window, you’ll likely feel hungry all the time and discouraged.” Moreover, it’s not like you have to fast all week. For example, people who follow the 5:2 diet—intermittent fasting—eat regular food for five days, then flip the switch on the other two days by reducing caloric intake. A 2021 study in PLoS One suggests that using the 5:2 method may be feasible for losing weight, partly because study participants reported feeling positive about it.
Avoid Overeating While Fasting
Intermittent fasting is about when you eat, not what or how much. If you consume too many calories while intermittent fasting, you’re not alone, says Mills. “It can be easy to overeat when a fast breaks, either because you’re feeling ravenous or you justify to yourself that you’re making up for lost calories.” Mills advises using a scale of zero to 10, where zero is famished and 10 is stuffed. “You should feel hungry before eating, and you should stop eating when you’re full, not just to clean your plate,” she explains. “It may take 15 to 20 minutes after you start eating for your brain to signal when you’re getting full.”
Say No to Soda While Fasting
Regarding beverages, soda is one of the worst choices when breaking a fast. “The carbonation in soda can mask your hunger, which can set you up for being too hungry at your next meal and lead you to overeat,” Mills says. “Artificially sweetened drinks can also raise the satisfaction bar for sweet tastes, so when you do eat a piece of fruit it may not be satisfying,” Mills adds that these beverages may also have caffeine, affecting people differently. “Some caffeine may make you jittery and set you up for craving sweets, while other caffeine may mask my sense of hunger and postpone eating until well past feeling hungry,” says Mills.
Keep Hydrated While Fasting
Generally, you should drink about 2 liters (that’s 1/2 gallon or 64 ounces) of water per day. “Water is part of metabolic reactions in our body and is necessary for it to function properly. Hydration prevents us from mistaking hunger for thirst,” says Mills. During snack breaks, opt for non-starchy veggies and fruits that contain water (yep, hydrating foods count toward your daily water goal!). Have sliced cucumbers, celery, watermelon, and oranges prepped in the fridge or your lunch bag.
Avoid Low-Protein, Low-Fiber Foods
You want to avoid low-protein, low-fiber foods when you break a fast. “Eating adequate lean protein, such as meat, poultry, and fish, as well as plant-based proteins like legumes, nuts, and seeds with each of your meals will help keep you full longer,” Mills says. Protein helps us feel full. Plus, protein will help maintain your metabolically active lean body mass if you lose a few pounds.” Another perk is that fiber from fruits, vegetables, whole grains, and legumes will slow the digestion and absorption of the carbs you eat, so you stay full and energized longer between meals. “Plus, choosing foods that provide protein and fiber will provide you with the vitamins, minerals, and nutrients you will need as you reportion your calorie intake,” adds Mills.
Don’t Go Overboard
Sure, you want to grab this diet trend by the lapels and run with it, but there’s no need to starve yourself. Taking in less than 1,200 calories per day might cause more significant weight loss—and significantly increased hunger—but also more excellent bone and muscle loss (which is where some of the lost weight will come from). The 2020-2025 Dietary Guidelines for Americans suggest that limiting calories to 1,200 per day is too low for most people to meet their nutritional needs, and it’s unsustainable for long-term health and well-being. Not to mention, if you make your window for eating too short, you won’t get all the nutrients you need, nor will you be able to stick with it for long. Make more minor, manageable changes and always listen to your body.
Don’t Quit Your Morning Coffee
Who said to ditch your morning joe, afternoon espresso, or warm tea? No one! Coffee isn’t bad for you. “A caffeinated beverage, especially if warm, is a comforting bridge between meals,” says Mills. Remember to avoid adding sugar or milk when you drink your cup while fasting.
Avoid Being Too Rigid
Whether you stick with intermittent fasting for a week or a month, it must feel like a natural part of your routine. “Shifting the focus to being more intuitive about when you eat based on your sensation of hunger and fullness is something that makes sense for a lifetime,” says Mills. “Choosing foods that nourish your body with the nutrients it needs to stay energized changes a calorie-counting mindset to a quality of life focus.” It’s less a diet mode and a new way of thinking about—and consuming—food.
Don’t Engage In Intense Workouts
You can exercise, just not like the Hulk. It’s hard to go all out in a workout if your tank is empty. Moderate exercise is essential for health benefits, but if you want to go a little more hardcore, ensure you’re not hours away from your next meal. Don’t hit the gym at 5 a.m. and not break your fast until 2 p.m. Your body needs fuel to get you through a challenging workout and to replenish your stores after one.
Don’t Give Up
Avoid throwing in the towel or beating yourself up if you eat at the “wrong time.” You won’t undo all your work with one meal, but you might have a bad attitude. Take the time to reassess and make sure the schedule you’ve set up continues to work with your lifestyle. Maybe it doesn’t anymore, and you want to shift your eating window or relax. That’s OK. Also, remember to focus on your food choices and eat as many high-quality, nutritious foods as possible. You won't be as hungry throughout the day if you have a healthy balance of protein, fiber, non-starchy veggies, and H2O.
Download DietAI Today for 80% Off!
If you want to keep track of your macros to help with intermittent fasting, DietAI is the app for you. This AI-powered app transforms calorie counting. Instead of manually logging every food you eat, you can snap a photo of your meal and instantly get detailed information on calories and macros without the tedious work. Whether you want to lose weight, gain muscle, or simply maintain a balanced diet, DietAI makes nutrition tracking effortless by eliminating the annoying aspects of traditional food journaling. Download now to effortlessly track your calories and macros with DietAI, the AI-powered app that makes logging meals as simple as snapping a photo.
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