Fasting has become an increasingly popular way to lose weight, improve health, and simplify eating habits. During fasting periods, only certain foods and beverages are allowed. Understanding what you can and cannot consume is crucial to remain in the fasted state and reap the potential benefits. This comprehensive guide outlines everything you need to know about what foods are acceptable when following common types of fasting protocols.
Water
Water is the staple beverage during fasting windows. Staying hydrated is vital to avoid dehydration, fatigue, and headaches. Plain water contains no calories, carbohydrates, proteins, or fats, making it ideal for fasting. Flavored seltzer waters and other carbonated waters can also be consumed during fasts.
Aim for 2-3 liters of total fluid intake per day while fasting for adequate hydration. Drinking water, seltzer, or other no-calorie beverages will not disrupt your fasted state.
Coffee and Tea
Coffee and tea (without added cream, milk, or sweeteners) do not contain calories and are perfectly acceptable during fasts. The caffeine in coffee, in particular, may provide an extra boost of energy and alertness needed when fasting.
Many people find black coffee and unsweetened green or herbal teas curb hunger cravings. Both provide antioxidants and other health benefits as well. Just be sure to avoid adding cream, milk, or caloric sweeteners like sugar, honey, or flavored syrups, as those ingredients will break your fast.
Apple Cider Vinegar
Apple cider vinegar (ACV) has recently gained popularity as a health tonic and weight loss aid. The acetic acid in ACV may have appetite suppressing effects. Diluting 1-2 tablespoons in water and sipping throughout the day is unlikely to influence fasting benefits. If consuming ACV helps you stick to your fast, it can be included during fasts. Just avoid mixing it with juices or other caloric ingredients.
Bone Broth
Bone broth is sometimes allowed during more flexible fasting protocols like alternate day fasting. On stricter fasts, bone broth is avoided since it does provide some calories and protein.
The consensus is about 50 calories per cup of bone broth. While a minimal amount, strict water fasts require 0 calories. But a cup of hearty bone broth once a day may be a good option on alternate day or 5:2 fasting protocols. The protein and nutrients can help curb hunger on fasting days.
Fruit and Vegetable Juices
Fresh juices made from fruits and vegetables are not usually recommended when following intermittent fasting protocols like 16:8. Even without pulp, juices contain natural sugars and calories that may technically break your fasted state.
However, during less restrictive alternate day or periodic fasting, juices may help provide nutrients and satiety on fasting days. Limiting juice intake to once per day in a small portion minimizes calorie intake while still providing phytonutrients.
Sports Drinks
Due to their calorie and carbohydrate content, sports drinks like Gatorade or Powerade do technically break a fast. Consuming calories stops ketosis and shifts the body out of the fasted state.
However, if doing prolonged bouts of intense exercise while fasting, having some sports drink may help maintain performance and prevent crashes in blood sugar. Just opt for lower calorie options and aim to keep intake under 50-100 calories during activity.
BCAA Supplements
Branched chain amino acids (BCAAs) supplements, especially leucine, have been shown to help maintain muscle mass while fasting. However, BCAA powders and capsules do contain calories and protein. Even a small dose of 5 grams provides 20 calories, which will take you out of the metabolic state of ketosis required for optimal fasting benefits.
If trying to maximize muscle retention, a small dose of BCAAs before a workout may be beneficial. But make sure to remain in the fasted state for the majority of the day to receive the other health and weight loss benefits.
Artificial Sweeteners
Artificial sweeteners like aspartame, sucralose, stevia, saccharin, and acesulfame potassium contain minimal or no calories. These can be technically allowed during fasts since they do not raise blood sugar or insulin levels.
However, some fasting experts advise avoiding sweet flavors altogether. Tasting sweetness may trigger food cravings and make fasting more difficult. If including sweeteners helps you remain compliant with your fast, they are generally permitted. But staying away from sweets may be easier for some people.
Bouillon Cubes
Bouillon or broth cubes contain some calories and nutrients, so they do break a strict fast. However, during intermittent fasting protocols less focused on ketosis, broth cubes can help provide sodium and other electrolytes.
Dissolving a bouillon cube in hot water makes a satisfying and compliant drink for fasts like 16:8. Just try to limit use to once a day. And avoid broth-based soups, which have higher calorie contents.
MCT Oil
MCT oil has been shown to help suppress appetite and enhance ketone production. Since it contains pure fat in the form of medium chain triglycerides, a small amount like 1 teaspoon generally will not disrupt ketosis during fasting.
However, you still are consuming around 45 calories per teaspoon. While minimal, using MCT oil may be better suited for less strict regimens like periodic fasting a few days per week rather than daily water fasts. Check with your healthcare provider before adding MCT oil while fasting.
Intermittent Fasting Beverage Options Summary
| Beverage | Allowed During IF? |
|---|---|
| Water | Yes |
| Sparkling Water | Yes |
| Black Coffee | Yes |
| Tea | Yes |
| Apple Cider Vinegar | In Moderation |
| Bone Broth | Limited Amounts |
| Fruit/Vegetable Juice | No |
| Sports Drinks | No |
| BCAAs | No |
| Artificial Sweeteners | Yes |
| Bouillon Cubes | In Moderation |
| MCT Oil | Limited Amounts |
What Foods Can Be Eaten During Intermittent Fasting?
In addition to timing, knowing what foods are suitable to eat during your “feeding window” on intermittent fasting plans is key. Here are the best options to include:
Lean Proteins
Chicken, turkey, and other lean meats, eggs, fish, and seafood are great sources of protein to eat when it’s time to break your intermittent fast. Protein is satiating and helps retain and build muscle mass when fasting. Salmon, tuna, and other fatty fish also provide anti-inflammatory omega-3s.
Non-starchy Vegetables
Leafy greens, broccoli, cauliflower, asparagus, peppers, mushrooms, tomatoes, and other non-starchy vegetables are very low in calories and carbohydrates. They provide nutrients and fiber that may help regulate blood sugar as well.
Legumes
Lentils, beans, peas, and chickpeas are excellent plant-based proteins to incorporate. They are a great source of fiber to help keep you feeling full too.
Nuts and Seeds
Almonds, walnuts, cashews, sunflower seeds, and pumpkin seeds make great high fat, plant-based snacks in moderation on intermittent fasting eating plans. They provide healthy unsaturated fats and may help curb cravings.
Whole Grains
Opt for minimally processed grains like quinoa, oats, brown rice, and 100% whole grain bread or pasta in your feeding window. The fiber helps control blood sugar spikes. Limit to a single serving with each meal.
Healthy Fats
Olive oil, coconut oil, nuts, seeds, avocado, and fatty fish provide filling healthy fats and omega-3s. Avoid processed vegetable oils. Using fat sources to dress salads or cook proteins enhances satiety.
Fruit
Berries and other fruits like grapefruit, apples, pears, and stone fruits can be eaten in moderation as part of a balanced intermittent fasting meal plan. Fruit provides antioxidants, vitamins, and minerals.
Dairy
Plain Greek yogurt and cottage cheese provide filling protein and minimal carbs. A small amount of milk or unsweetened dairy alternatives can be included for calcium needs as well. Avoid sweetened dairy products.
Foods to Avoid While Intermittent Fasting
Some foods are not suitable for eating during your condensed feeding window when following intermittent fasting protocols:
Refined Carbs
Foods made with white flour and added sugars spike blood glucose and may lead to crashes and cravings. Avoid bread, pasta, cereals, baked goods, and other refined carbs.
Sugary Drinks
Avoid sodas, juices, sweetened coffees and teas, and other drinks high in sugar to prevent unstable blood sugars. Stick to water, seltzer, and unsweetened beverages.
Processed Snack Foods
Chips, pretzels, crackers, and other processed grain-based snacks are easy to overeat and not very nutritious. They may trigger cravings for more junk food as well.
Desserts
Cookies, cakes, ice cream, and other sweets provide empty calories and extra carbohydrates that are best avoided, especially during the shorter eating windows of intermittent fasting plans.
Fried Foods
Fried foods like french fries, chicken nuggets, and fried cheese tend to be high in calories but low in nutrients. They also contain unhealthy trans fats that may promote inflammation.
Condiments
Ketchup, mayonnaise, salad dressings, and dipping sauces are often packed with added sugars, refined oils, and preservatives so use them sparingly.
Alcohol
Alcoholic beverages tend to be high in empty calories and carbohydrates, so they are not recommended on intermittent fasting routines, especially during the fasted state.
Sample Meal Plans for 16:8 Intermittent Fasting
Here are a couple sample meal plans showing healthy food choices to eat during the 8 hour “feeding window” on a 16:8 intermittent fasting schedule:
Sample Day 1
Meal 1:
– Omelet with spinach and feta cheese
– Mixed berries
– Bulletproof coffee
Meal 2:
– Turkey burger on a lettuce wrap
– Kale salad with walnuts and balsamic vinaigrette
– Greek yogurt with cinnamon
Sample Day 2
Meal 1:
– Protein smoothie with almond milk, protein powder, peanut butter and frozen banana
– Cottage cheese with tomatoes and avocado
Meal 2:
– Grilled salmon
– Asparagus
– Brown rice
– Dark chocolate square (1 oz)
Should You Exercise While Fasting?
Light to moderate intensity exercise during fasting periods can be beneficial but is optional. Studies show working out in a fasted state may help burn more fat compared to exercising after eating.
However, exercise depletes glucose so high intensity or endurance workouts may be tougher without fuel. Make sure to stay hydrated and listen to your body. If you feel low energy, light-headed, or ill, stop exercising.
Save vigorous workouts for your “feeding” period when you can replenish with food and drinks. And if training for an intense event, some pre-exercise fuel may be prudent for performance.
Precautions with Fasting
Fasting is not suitable for everyone. Check with your healthcare provider before starting, especially if you:
– Have diabetes or blood sugar issues
– Are underweight
– Have a history of disordered eating
– Are malnourished
– Have nutritional deficiencies
– Are pregnant or breastfeeding
When starting out, begin with more moderate routines like 12:12 or 14:10 before progressing to longer fasting periods. Stop immediately if you experience side effects like fatigue, dizziness, nausea, or other concerning symptoms.
Bottom Line
Following the proper protocol for your intermittent fasting plan is crucial. Stick to plain water, black coffee, and other no-calorie beverages during the fasting period. When it’s time for your eating window, focus on lean proteins, non-starchy vegetables, healthy fats, and minimally processed whole food sources. Avoid sugary and refined foods which can spike blood sugar.
Paying attention to nutrition quality and following the intermittent fasting beverage and food rules will help your body stay in ketosis so you reap the full benefits. That being said, adhere to a routine that feels sustainable. Some flexibility is okay, especially when first adapting to fasting. With consistency over time, intermittent fasting may help improve body composition, mental clarity, and biomarkers of health.