The low-carb intermittent fasting (LCIF) diet combines the principles of carbohydrate restriction with intermittent fasting (IF). This approach involves cycling between periods of eating and fasting, while also limiting carbohydrate intake during eating windows. Meals typically include low-carb vegetables, high-quality proteins, and healthy fats.
Introduction to Low-Carb Intermittent Fasting
The Intermittent Fasting meal plan for a low-carb diet combines the benefits of IF with a low carbohydrate intake. This dietary strategy aims to maximize the effectiveness of both approaches, potentially leading to healthy weight loss, improved control over food intake, and accelerated fat burning.
What is Intermittent Fasting?
Intermittent fasting (IF) is an eating pattern that alternates between fasting and eating windows. It focuses on when you eat, rather than what you eat, making it a flexible option for many lifestyles. The most common approach is the 16/8 method, where you fast for 16 hours and eat within an 8-hour window. According to research, the 16/8 method is the easiest to maintain and integrate into a routine, especially when compared to a detox meal plan.
Understanding Low-Carb Diets
A low-carb diet restricts carbohydrates, such as those found in pasta, bread, and sugary foods. It’s high in protein, fat, and vegetables. People often use low carb diets to promote weight loss and stabilize blood sugar levels. Though guidelines can vary, low carb diets typically limit foods high in carbs or added sugar. A typical low carb diet usually contains less than 26% of total daily calories from carbs. For those following a 2000-calorie diet, this equals fewer than 130 grams (g) of carbs per day.
Foods to Eat and Avoid
Foods to Eat
- Low-Carb Vegetables: Leafy greens, broccoli, and bell peppers for vitamins and minerals with minimal carbs.
- Lean Proteins: Chicken, fish, and eggs for sustained energy and muscle maintenance.
- Healthy Fats: Olive oil, nuts, and avocados for satiety and good fats.
- Nuts and Seeds: Almonds, chia seeds, and flaxseeds for fiber and omega-3 fatty acids.
- Low-Sugar Fruits: Berries and melons in moderation.
- Hydration: Water, herbal teas, and unsweetened beverages to maintain hydration.
- Dairy or Alternatives: Cheese and Greek yogurt in moderation, avoiding high-lactose options.
- Lean Dairy Alternatives: Such as almond milk and coconut yogurt.Experiment with incorporating a variety of herbs and spices into your meals to add flavor without relying on high-carb sauces or condiments.
Foods to Avoid
- Starchy Vegetables: Such as potatoes, corn, and peas.
- High-Sugar Fruits: Bananas, grapes, and tropical fruits.
- Grains: Bread, pasta, rice, and cereal, which are high in carbohydrates.
- Legumes: Beans and lentils, while nutritious, are high in carbs.
- Sugary Snacks: Candies, cookies, and cakes.
- Sweetened Beverages: Soda, sweetened teas, and fruit juices.
- Processed Foods: Even if labeled "low carb", they often contain hidden carbs and unhealthy additives.
- Alcohol: Many alcoholic drinks are high in carbs and sugars.
Types of Low-Carb Diets
There are several types of low carb diets, and they differ based on the amount of carbs permitted each day. Here are a few of the most popular low carb eating patterns:
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- Ketogenic (keto) diet: This low carb, high fat eating pattern limits daily carb intake to less than 5-10% of total calories, or around 20-50 g of carbs.
- Atkins diet: During the first phase of this diet, carb intake is limited to about 20 g per day, depending on which plan you choose. Over the duration of the diet, your intake gradually increases but typically doesn’t exceed 100 g per day.
- South Beach diet: Besides reducing carb intake, this diet encourages you to eat lean meats and heart-healthy fats. During the initial phase, grains and fruits are also off-limits.
- Paleo diet: This diet mimics the eating patterns of our hunter-gatherer ancestors and is naturally low in carbs.
- Dukan diet: The diet restricts carbs while being high in protein and low in fat. It’s divided into four phases to help you reach your weight loss goals.
Benefits of Low-Carb Intermittent Fasting
Combining intermittent fasting and a low-carb diet may offer several advantages:
- Weight Loss: Intermittent fasting helps you lose weight by restricting the amount of time you can eat during the day. Adding a low-carb diet to this equation can further enhance weight loss. By limiting your carbohydrate intake, you decrease insulin production and increase the breakdown of stored fat for energy.
- Better Digestion and Gut Health: Low-carb diets are often easier on the digestive system than high-carb diets. Intermittent fasting also allows the digestive system to rest and repair during the fasting period, potentially leading to improved gut health.
- Improved Brain Function: Low-carb diets provide the brain with a steady source of energy through the production of ketones, which are an alternative to glucose. Intermittent fasting may also trigger the production of BDNF (brain-derived neurotrophic factor), a protein that promotes the growth and protection of neurons in the brain.
- Reduced Inflammation: Inflammation is the body’s natural response to injury or illness. Both low-carb diets and intermittent fasting are believed to have anti-inflammatory effects on the body.
- Increased Energy Levels: Many people have reported an increase in energy levels when following a low-carb and intermittent fasting diet.
- Lower Risk of Chronic Diseases: Some studies have suggested that intermittent fasting and/or low-carb diets may improve insulin sensitivity and blood sugar control in individuals with or at risk for type 2 diabetes. This suggests that this approach may be beneficial for managing and potentially reversing this condition.
Potential Drawbacks
- Difficulty Adapting: One of the main challenges with this approach is adapting to a new way of eating.
- Potential Nutrient Deficiencies: Restricting certain food groups, such as carbohydrates, can lead to nutrient deficiencies if not carefully planned. In addition, intermittent fasting may lead to a lower intake of certain nutrients if not carefully planned.
- Potential for Overeating: Following a low-carb diet and intermittent fasting may also trigger overeating during eating periods.
- Not Suitable for Everyone: Like any diet or lifestyle change, low-carb intermittent fasting may not be suitable for everyone.
Tips for Success on a Low-Carb Intermittent Fasting Diet
- Start with Either Approach, Not Both Together: To ease into this diet, it may be helpful to start with either a low-carb or intermittent fasting approach first. This will help your body adapt gradually without overwhelming it with too many changes at once. It is often recommended to start with a low-carb diet first as this may be most challenging. Carbs are often a major part of traditional diets, so cutting them out can be a major adjustment.
- Meal Plan and Prep: Planning and prepping meals is essential for success on this diet. Set aside time each week to plan your meals and make a grocery list of the necessary ingredients. It’s important to remember that hydrating is important during both eating and fasting periods.
- Plan for Social Situations: Dining out or going to events with friends and family can be challenging when you’re following a low-carb intermittent fasting diet. To make things easier, plan ahead by checking the menu of the restaurant beforehand and choosing a lower carb option or opting for a smaller portion size.
- Adopt a Gradual Approach and Listen to Your Body: A common pitfall when dieting is to go too strict or extreme straight away, which can lead to burnout and eventually giving up. You should adopt a gradual approach and listen to your body’s needs. If you feel you need more carbs on certain days, then you should incorporate them in moderation.
Sample Meal Plans
7-Day Intermittent Fasting Meal Plan (16/8 Method)
This 7-day meal plan follows the 16/8 intermittent fasting approach, with an eating window from 12:00 PM to 8:00 PM. Each meal is packed with nutrients to keep you full, energized, and satisfied. Feel free to adjust meal timings based on your preferences and lifestyle.
- Day 1
- Breakfast (12:00 PM): Scrambled eggs with avocado and whole-grain toast
- Snack (3:00 PM): Greek yogurt with almonds and berries
- Lunch (5:30 PM): Grilled chicken salad with quinoa and olive oil dressing
- Dinner (7:30 PM): Salmon with roasted sweet potatoes and steamed broccoli
- Day 2
- Breakfast: Oatmeal with peanut butter and banana
- Snack: Hard-boiled eggs and hummus with cucumber slices
- Lunch: Spicy turkey meatballs with roasted veggies
- Dinner: Thai beef lettuce wraps
- Day 3
- Breakfast: Spinach and cheese omelet with a whole-grain wrap
- Snack: Apple slices with almond butter
- Lunch: Grilled chicken with brown rice and sautéed greens
- Dinner: Italian meatball soup
- Day 4
- Breakfast: Chia pudding with walnuts and cinnamon
- Snack: Cottage cheese with berries and pistachios
- Lunch: Chicken fajita bowl with quinoa
- Dinner: Baked salmon with roasted cauliflower
- Day 5
- Breakfast: Avocado toast with poached eggs
- Snack: Roasted chickpeas with turmeric
- Lunch: Lentil soup with a mixed greens salad
- Dinner: Grilled steak with mashed sweet potatoes
- Day 6
- Breakfast: Protein smoothie with almond milk, banana, and flaxseeds
- Snack: Dark chocolate and nuts
- Lunch: Mediterranean quinoa bowl with feta cheese and chickpeas
- Dinner: Baked cod with roasted zucchini and garlic butter
- Day 7
- Breakfast: Greek yogurt with granola and berries
- Snack: Boiled eggs with avocado slices
- Lunch: Vegetable stir-fry with tofu and brown rice
- Dinner: Chicken tortilla soup with a side salad
3-Day Sample Low-Carb Menu
This is a sample menu for 3 days on a low carb diet plan. That said, ask a doctor or dietitian what carbohydrate allowance works best for you based on your health goals and personal preferences.
- Day 1
- Breakfast: 2 slices sprouted Ezekiel bread with 1/2 avocado, salt, and pepper. Total carbs: 36.5 g.
- Lunch: 3 ounces (oz) (85 g) grilled chicken with 2 cups (340 g) zucchini noodles made with 1 clove of garlic, butter, and 1 oz (28 g) Parmesan. Total carbs: 17 g.
- Dinner: bunless burger with a slice of Cheddar cheese, served with 1/2 cup (78 g) cooked broccoli and 2 tablespoons (35.7 g) of salsa. Total carbs: 8.5 g.
- Total carbs for the day: 62 g
- Day 2
- Breakfast: 7 oz (200 g) plain Greek yogurt with 1/4 cup (37 g) blueberries and 1 oz (28.35 g) almonds. Total carbs: 19.4 g.
- Lunch: 3 oz (85 g) rib eye roast with 1/2 cup (120 g) mashed rutabaga and 1 cup (129 g) sautéed green beans. Total carbs: 13.5 g.
- Dinner: 3 oz (85 g) baked salmon with 1/2 cup (90 g) cooked asparagus and 3/4 cup (85 g) cauliflower rice. Total carbs: 7.7 g.
- Total carbs for the day: 40.6 g
- Day 3
- Breakfast: breakfast bowl with 2 large hard-boiled eggs, 1 tomato, and 1 cup cubed avocado. Total carbs: 19 g.
- Lunch: 2.5 cups (244 g) shrimp garden salad with shrimp, lettuce, eggs, tomato, and carrots, with 2 tablespoons (tbsp), or 30 milliliters (mL), olive oil vinaigrette. Total carbs: 10.5 g.
- Dinner: 3 oz (85 g) grilled chicken with 1/2 cup (78 g) roasted Brussels sprouts and 1/2 cup (93 g) cooked quinoa. Total carbs: 25.2 g.
- Total carbs for the day: 54.7 g
Healthy Low-Carb Snacks
If you get hungry between meals, here are some healthy, easy-to-prepare, low carb snacks that can fill you up: a piece of fruit, Greek yogurt, one or two hard-boiled eggs, baby carrots, leftovers from the previous night, a handful of nuts, some cheese and meat.
Dining Out on a Low-Carb Diet
Following a low carb diet while dining out can be challenging. Not only are the portion sizes often very large, but some restaurant foods are served with condiments, sauces, or side dishes that are high in added sugar or carbs. Still, at most restaurants, making your meals low carb is fairly easy.
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Here are a few tips to get started:
- Opt for a meat- or fish-based main dish.
- Choose plain water instead of sugary soda or fruit juice.
- Get extra vegetables or a side salad instead of bread, potatoes, or rice.
- Check the menu beforehand to find options that fit your daily carb allowance.
- Ask for sauces, condiments, or dressings on the side so you can control your portion sizes.
- Consider taking half of your meal “to go” to reduce the amount of carbs during your restaurant meal.
Addressing Common Questions
- What should I eat on a no-carb day? If you’re avoiding carbs entirely, focus on eating animal and plant-based proteins and plenty of vegetables and fruit. That said, your body does need some carbs, so avoiding them entirely, unless directed by your doctor, may not be the best for your health. It’s also less sustainable than including a small amount in moderation.
- How do I stay under 20 carbs a day? (This requires careful planning and adherence to a ketogenic diet)
- What’s a good low carb diet plan for a vegetarian? You can follow a low carb diet as a vegetarian, but it can be more challenging because most plant-based protein foods also contain carbs. It’s important to ensure you’re getting enough calories and nutrients, so consulting with your doctor or a registered dietician is a good idea.
- What’s a good low carb diet plan for diabetes? Research shows that following a low carb diet while living with diabetes can help you manage the disease. Eating low carb with diabetes is similar to eating low carb without diabetes. You can generally eat and avoid the same foods. That said, you’ll need to track your blood sugar and follow the diabetes treatment prescribed by your doctor.
- Are Carbs OK on Intermittent Fasting? You can absolutely eat carbs while practicing IF. During the fasting period, you’re encouraged to drink water or other non-caloric beverages, but food intake is restricted. IF is an eating pattern, not a diet. Carbs are an important source of energy and a major fuel for the brain and muscles, and they help with physical and mental performance.
- Can I do intermittent fasting without keto? Yes, you can do intermittent fasting without following a keto diet.
Scientific Studies and Research
Alternate day fasting (ADF) is a popular weight loss regimen. Whether carbohydrate restriction can enhance the weight loss achieved with ADF remains unclear. Adults with obesity (n = 31) participated in ADF (600 kcal “fast day” alternated with an ad libitum “feast day”) with a low‐carbohydrate background diet (30% carbohydrates, 35% protein, and 35% fat).
- Body weight decreased (−5.5 ± 0.5%; P < .001) during the weight loss period (month 0‐3) but remained stable (P = .57) during the weight maintenance period (month 4‐6). Net weight loss by month 6 was −6.3 ± 1.0%.
- Fat mass was reduced (P < .01) by month 6, while lean mass and visceral fat mass remained unchanged.
- Total cholesterol and low‐density lipoprotein (LDL) cholesterol levels decreased (P < .05) by −6 ± 2% and − 8 ± 3%, respectively, by month 6.
- Systolic blood pressure was also reduced (P = .03) by −7 ± 3 mm Hg.
- Fasting insulin decreased (P = .03) by −24 ± 8% by month 6 relative to baseline.
These findings suggest that ADF combined with a low‐carbohydrate diet is effective for weight loss, weight maintenance, and improving certain metabolic disease risk factors such as LDL cholesterol, blood pressure, and fasting insulin.
The Intermittent Fasting Carb Cycle
This combines Intermittent Fasting with Carb Cycling. Each week you’ll choose three low-carb days, three moderate-carb days and one high-carb day. It doesn't matter what days of the week these fall on, and you can change days as you go. For example, you may get a sudden dinner invitation and decide to make that your high-carb day.
On your three low-carb days, you’ll consume either 0.5 gram or 0.25 gram of carbs per pound of body weight, depending on your current diet. On your three moderate-carb days, you’ll eat either 0.5 gram per pound or 1 gram per pound. On your weekly high-carb day, you can eat pretty much as many carbs as you want. Be sure to eat at least 2 grams per pound of bodyweight on this day, and up to 4 grams per pound.
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With your carbs set for each day of the week, the other two macronutrients to fit into your diet equation are protein and fat. Every day, regardless of whether you’re going low, moderate or high on carbs, you want to eat a bare minimum of 1 gram of protein per pound of body weight. Ideally, you should be hitting around 1.5 grams, especially on the low-carb days. On the high-carb day and even moderate carb days, protein can be closer to 1 gram, but still shoot for 1.5. Just don't kill yourself if you don't get there - unless you’re under 1 gram. You should shoot for 0.5 gram of dietary fat per pound of body weight daily.
Another timing rule with IF is to train within or right before your feeding window. It's critical to have certain nutrients available around workouts for optimal gains in muscle strength, endurance, muscle growth and even fat loss.