IIFYM (If It Fits Your Macros) Guide to Lose Weight

IIFYM is a flexible diet that doesn’t set rules or restrictions on your food choices. By simply manipulating your macronutrient intake, IIFYM can help you lose or gain weight, depending on your goals.

Not only is IIFYM simple and easy to follow, but it can also help promote accountability and awareness about your food choices. It may also be a good choice for those who want to achieve their goals while still enjoying their favorite foods in moderation.

Keep reading for everything you need to know about IIFYM, including some of the benefits, downsides and step-by-step instructions for how to follow it.

What Is IIFYM?

IIFYM, also known as “If It Fits Your Macros,” is a type of eating plan focused on the macronutrients you consume. Instead of counting calories (such as in the CICO diet), the IIFYM diet plan involves tracking your intake of protein, fat and carbohydrates.

The concept of IIFYM was developed by Anthony Collova, who became tired of traditional diets and started manipulating his macronutrient intake to lose weight.

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Since its inception, the internet has been flooded with IIFYM reviews, both positive and negative. While some claim that it is a flexible and effective method to lose weight, others note that it could contribute to unhealthy eating habits and may not be a good fit for everyone.

Calculating Macros

Calculating your macronutrient intake is a cornerstone of the IIFYM diet. The IIFYM website offers a free tool to determine your needs, making it easy to start adjusting your diet and tracking your nutrient intake.

However, you can also figure out your macronutrient needs manually. Here are some simple steps for how to count macros.

1. Determine Basal Metabolic Rate

Basal metabolic rate is a term used to describe the amount of calories that your body burns at rest, based on your age, height and body weight. The free IIFYM macro calculator can help you determine this number easily, but you can also plug in your information to the following equation to determine your needs:

• Men: 66.47 + (6.24 x weight in pounds) + (12.7 x height in inches) − (6.755 × age in years)
• Women: 655.1 + (4.35 × weight in pounds) + (4.7 x height in inches) − (4.7 × age in years)

2. Account for Physical Activity

Because your basal metabolic rate only measures the amount of calories burned at rest, it’s important to account for any physical activity that you do during the day. To do this, simply multiply your basal metabolic rate by an activity factor, which should be based on how physically active you are.

• Sedentary: x 1.2 (very limited exercise)
• Lightly active: x 1.375 (light exercise three days or fewer per week)
• Moderately active: x 1.55 (moderate exercise most days each week)
• Very active: x 1.725 (hard exercise daily)
• Extra active: x 1.9 (intense exercise twice per day)

3. Adjust Based on Goals

Once you’ve calculated how many calories you should consume each day in order to maintain your weight, it’s time to adjust based on your specific weight goals.

If you want to lose weight, you should decrease your caloric intake by around 15 percent to 20 percent. Conversely, if you’re hoping to gain weight, increase your daily calorie goals by 5 percent to 10 percent.

4. Calculate Macronutrient Needs

Next, it’s time to determine the macronutrient ratio you should aim for.

According to the IIFYM website, you should consume at least 0.8 grams of protein and 0.3–0.4 grams of fat per pound of lean body weight. The remaining calories in your diet should come from carbohydrates, with around 20 percent to 25 percent of your lean body weight (in grams) coming from fiber.

You can also switch up your macronutrient ratio to fit your needs. Typically, it’s recommended to aim for about 45 percent to 65 percent of calories from carbs, 20 percent to 35 percent from fat and 10 percent to 35 percent from protein.

5. Start Tracking

Once you’ve determined your macronutrient and calorie needs, it’s time to start monitoring your intake. Use an online fitness tracker or food journal to track your intake and ensure that you’re sticking to your macronutrient goals.

Meal Plan

Here is a sample meal plan (along with some healthy IIFYM recipes) based on an 1,800-calorie diet with around 45 percent to 65 percent of calories from carbs, 20 percent to 35 percent from fat and 10 percent to 35 percent from protein.

Day One

• Breakfast: 2 scrambled eggs with 1/2 cup spinach, 1/2 cup mushrooms and 1/2 cup carrots + 2 pieces of sprouted wheat bread with 1 tbsp. grass-fed butter
• Lunch: 4 oz. baked chicken + 1 cup sweet potato wedges + 1 cup steamed broccoli + 1/2 cup cooked quinoa
• Dinner: 1 cup zucchini noodles with 2 tbsp. pesto and 4 oz. Baked Meatballs + 1 cup roasted asparagus
• Snacks: 1 medium apple with 2 tbsp almond butter + 1 banana

Day Two

• Breakfast: 1/2 cup oatmeal with 1/2 cup strawberries, 1/2 cup blueberries, 1 oz. almonds and cinnamon
• Lunch: Teriyaki Baked Salmon + 1 cup Brussels sprouts + 1 cup herbed couscous
• Dinner: burrito bowl with 1 cup cooked brown rice, 1/2 cup black beans, 1 sliced tomato, 1/2 avocado, 2 tbsp. salsa and cilantro
• Snacks: 1 cup Greek yogurt with 1 tbsp. chia seeds + 1 medium orange

Day Three

• Breakfast: green smoothie with 1 cup oat milk, 1 scoop protein powder, 2 cups spinach and 1 cup mixed berries
• Lunch: veggie burger with 1/2 sliced avocado + medium baked potato with 1 tbsp. grass-fed butter + 1 cup sautéed garlic kale
• Dinner: 3 oz. Grilled Garlic Lemon Chicken + 1 cup roasted cauliflower + 1/2 cup cooked farro
• Snacks: 1 oz. pistachios + 1 cup carrots with 2 tbsp. hummus + 1 cup grapes

Health Benefits

The IIFYM diet may be associated with several benefits. Here are a few of the top reasons to consider this popular eating plan.

1. May Increase Weight Loss

For many, following the IIFYM results in increased weight loss and improved body composition. This is primarily because it involves reducing your caloric intake, which is an important component of weight loss.

It’s also relatively high in protein, which has been shown to reduce appetite, caloric intake and body weight. Plus, protein has also been shown to decrease levels of ghrelin, the hormone that is responsible for stimulating feelings of hunger.

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However, keep in mind that potential IIFYM weight loss can vary quite a bit depending on the quality of your diet. Filling your diet with processed foods that are lacking in nutrients, for example, may not be as effective for weight loss or overall health.

2. Could Improve Diet Quality

The IIFYM plan doesn’t set any restrictions on which foods are allowed. While this does leave room for error and unhealthy choices like fast food, convenience meals or processed ingredients, it is much easier to focus on nutritious whole foods that can fit into your daily macronutrient ratio.

Ideally, a healthy IIFYM diet should actually improve the quality of your diet by prioritizing nutrient-dense foods containing a good mix of protein, fat and carbs.

3. Promotes Accountability

IIFYM requires you to track all foods that you eat during the day to help ensure that you’re sticking to your macronutrient goals. This can help prevent grazing or snacking throughout the day to help keep you accountable.

Studies show that keeping a food journal could potentially improve weight loss. According to a 2019 study in the journal Obesity, recording daily dietary intake was significantly associated with increased weight loss.

What’s more, participants got even faster at logging their daily intake and slashed the amount of time spent by 37 percent over the course of the six-month study.

4. Flexible and Easy to Follow

Dieters often enjoy the flexibility of the IIFYM diet because it’s simple, easy to follow, and doesn’t have the same strict rules and regulations as other diets. Instead, nearly any food can be enjoyed, as long as it fits into the allotment for IIFYM protein, fat and carbs.

While this doesn’t mean that you should load up on the junk food, you may still be able to enjoy your favorite treats in moderation from time to time.

Risks and Side Effects

There are several risks and downsides associated with following an IIFYM meal plan. First of all, the diet focuses solely on macronutrient intake but doesn’t necessarily account for the quality of your diet.

In fact, just about any food can fit into the diet, including processed ingredients like fried foods, chips, crackers and cookies. Focusing on nutrient-dense, whole foods not only makes it easier to meet your macronutrient goals, but it can also improve the overall quality of your diet and ensure that you’re getting the vitamins and minerals that you need.

Because the diet requires you to carefully track and monitor your food intake, it can also promote unhealthy eating habits. For this reason, it’s often not recommended for those with a history of disordered eating.

It also requires a good amount of time and effort to weigh and log everything that you eat. Because of this, it may also interfere with certain social situations and can be problematic for some people.

On the IIFYM diet, it can also be easy to slip into a routine and select the same go-to foods that you might be more comfortable with. However, this can decrease the diversity of your diet and make it harder to get the range of important vitamins, minerals and antioxidants that your body needs.

Final Thoughts

• What is IIFYM? “If It Fits Your Macros,” or IIFYM, is an eating plan that focuses on the macronutrients that you consume.
• To calculate your ideal macronutrient ratio, you can use an IIFYM calculator or determine your needs manually.
• Tracking your macronutrient intake may help increase weight loss, improve diet quality and promote accountability. The diet is also very flexible and easy to follow.
• On the other hand, the diet doesn’t prioritize high-quality ingredients, can promote unhealthy eating habits, may decrease diet diversity and can be very time-consuming.
• If you do decide to follow an IIFYM diet, be sure to include a variety of healthy, whole foods in your meal plan to maximize the potential health benefits.