• If your goal is to lose weight, any diet that restricts calories will get you that exact result. “If it fits your macros” (IIFYM) and “Clean” eating are certainly useful ways to achieve weight loss. As shown through the famous Twinkie diet by a professor of human nutrition.¹
  • Isn’t it all about calories? Not all calories are equal. Your hormonal balance depends on largely where your macronutrient sources come from. 100g of carbohydrates from sugar (e.g. Mars bar) and 100g of carbohydrates from “Clean” food (e.g. Root vegetables) will have a different impact on your insulin sensitivity levels.
  • Low levels of chronic systematic inflammation will be present from a higher dosage of sugar intake. At as little as 40g of added sugar per day you raise your blood inflammation markers (hs-CRP) by 60-109%.2 The evidence is now strong and clear that “An unresolved inflammatory response is likely to be involved from the early stages of disease development.”3 (If you’re interested in how sugar causes systematic inflammation read reference 4)
  • Most IIFYM advocates generally have significant muscle mass already, effectively raising their basal metabolic rate (BMR) compared to untrained individuals and also they are more insulin sensitive.
  • Most IIFYM advocates choose to portray the junk food portion of their diet to the public but leave out the other 80% of the diet. You are not getting the full picture.
  • Most clients’ starting point is not suitable for IIFYM.
  • Follow the 80/20 Rule. If you eat “clean” foods most of the time the other 20% of the time can be junk food.
  • It pays off big time to be strict and eat “clean” foods only.

What to expect: 2200 word – 10 minute read


The most important factor that determines your body composition results and your health is energy balance. This is the amount of calories going into your body from food and drinks versus the amount of calories that go out of your body from your basal metabolic rate, non-exercise activity thermogenesis (NEAT), activity level and thermic effect of food. If a deficit of energy is achieved through dieting you will have weight loss. When you accumulate 3500 kcal deficit (over any time period), you lose one pound of fat. If you are achieving 500 kcal deficit per day, you should lose 1lbs of fat per week. However, if you’re consuming calories at an unaccounted rate, you generally will be in a caloric surplus and gain weight over time. Thus any diet that restricts your calories is going to help you lose weight, this includes IIFYM, clean eating, low carb, no carb, ketogenic diet, high carb low fats and whatever fad diet.

Example: Let’s say your body type is a typical Asian woman working in the office, in my experience most of these women have a maintenance calorie of about 1400 kcal per day. So for these women, they should be eating less than 1400 kcal per day in order to achieve fat loss, but not at such a great deficit (1000 kcal below maintenance calories) that all important vitamins, minerals, and macronutrient needs are not met. If these women are eating 1200 kcal per day, that puts them at a 200 kcal deficit daily; for them to lose 1lbs of fat then takes 17.5 days. Not impressive, right? A greater daily deficit should be achieved NOT by cutting more calories but to increase activity level. Best results are achieved by a combination of weight lifting and cardio training.

What is IIFYM diet and “Clean” eating?

We now know that just by being in a caloric deficit you will lose weight, we will now delve deeper into what is IIFYM dieting and “Clean” eating.

IIFYM stands for “If it fits your macros” and this is how you practice IIFYM. First set a number of calories depending on your goals (deficit calories for fat loss/surplus calories for weight gain) and then choose your macronutrient percentages. Ideally for training individuals, I suggest “high carbs/low fats/medium protein diets”; however, for a brand new obese client with a very low starting point, this could be problematic due to their bad insulin sensitivity and nutrient partitioning. For these type of clients, I usually put them on a “low carbs/high fats/medium protein” diet for a short amount of time to boost their insulin sensitivity. Once the macronutrient ratios are set, you basically consume any food that will allow you to hit those macronutrient goals; be it from junk food, processed foods, sugar or healthy foods.

Consider following example:

1800 kcal. The goal is fat loss for an average sized male. Macronutrient ratios as follows: 160g Protein/80g Carb/93g Fat.

Breakfast: 2 Eggs/1 Tbsp Oil/5 pieces of bacon
Post workout: 2 scoops Whey Protein Isolate
Snack 1: Mars bar (standard UK sized)
Lunch: 6 MacDonald’s Chicken nugget/50g sweet chili dipping sauce
Snack 2: 5x Maltesers
Dinner: 230g Salmon steak cooked with half teaspoon oil

Food Total: 1831kcal 158g Protein/97g Carb/95g Fat

Does that diet look healthy to you? Bear in mind that it is a given that eating the above will allow you to have weight loss from muscle and fat if you don’t add in resistance training or fat loss with a mixture of cardio and resistance training (given that your maintenance calories are above 1800 kcal. IIFYM argues that you can eat anything so long as your daily calorie and macronutrient goals are met, if you look at the “Food Total” above, on paper the diet is perfectly healthy, there is a good amount of protein, not extremely low on carbs, high in fats. A good friend of mine once asked me “can you lose weight eating chicken nuggets?” It is evident in 2010 when Mark Haub, a professor of human nutrition at Kansas State University, ate a Twinkie every 3 hours instead of meals supplemented with Doritos chips, sugary cereals, and Oreos for 10 weeks and shed 27 pounds in two months. ¹ So my answer was “Absolutely”, but is it ideal? Of course not! Why? I’ll touch upon that below.

“Clean” eating, as most people would call it, basically means eating healthy foods. Unless you sterilized your food by dipping it into isopropyl alcohol before every bite, please don’t call it “Clean” eating, there is no such term for food description; it’s called eating healthy. What constitutes healthy foods then, usually it is foods that cause a low inflammatory response in your body. The following is a list of foods that are most nutrient/mineral dense to the least but still healthy. Fruits/Vegetables/Lean meats/Nuts/Whole foods/Complex carbohydrates.

A sample diet of healthy eating with the same calories needs as above would look like this:

Breakfast: 1 Avocado (200g)/Wholewheat Bread 2 slices/40g Acacia Honey/2 Eggs
Post Workout: 2 Scoop whey protein isolate
Snack: 15 Almond nuts
Lunch: 300g Sole fish fillet/green vegetables
Dinner: 150g Ribeye steak/cooked with half teaspoon oil/green vegetables
Food total: 1840 kcal 162g Protein/60g Carb/70g Fat


Breakfast: 2 Eggs/1 Tbsp Oil/5 pieces of bacon
Post workout: 2 scoops Whey Protein Isolate
Snack 1: Mars bar (standard UK sized)
Lunch: 6 MacDonald’s Chicken nugget/50g sweet chili dipping sauce
Snack 2: 5x Maltesers
Dinner: 230g Salmon steak cooked with half teaspoon oil



Consider the two diets above, which one is healthier despite the two having an equal number of calories and macro-nutrients split.

The healthy eating habits are bound to leave you feeling better, stronger, recover better, better skin and better result than IIFYM. Why? You must first consider a couple things when choosing between these diets, namely low levels of chronic systematic inflammation, gut health, hormonal balance (Insulin secretion being the main one), the toxic load on the body and the micronutrients found in the foods.


When the certain dosage of added sugar (40g per day) is present in one’s diet it raises their inflammation markers by 60%-109%.2 It is a well-known fact that the early stages of a host of diseases are attributed to prolonged periods of chronic low-grade inflammation. Systematic inflammation causes elevated cortisol levels and cortisol has a catabolic effect on the body which will inhibit your gain in FFM. Cortisol is also responsible for raising blood sugar levels (the direct opposite of insulin’s function) and constantly elevated blood sugar levels also elevate your insulin level to control blood sugar, in simple terms, you become insulin resistant (early stages of diabetes) and require more insulin to do the same job. It is a vicious cycle. Systematic inflammation will also “lead to less flexible and less permeable cell membranes that have reduced ability to transport nutrients into your cells and to rid the cells of wastes. The cells will also have impaired ability to communicate with one another.”5


Did you know a human being has up to 2kg of microorganisms in their gut alone? This is what is commonly referred to as gut microbiota. “Relation between the gut microbiota and human health is being increasingly recognised. It is now well established that a healthy gut flora is largely responsible for the overall health of the host.” “The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens.”6 If you increase your toxic load and sugar intake you will not have a healthy ratio of gut microbiota, in turn, you can’t metabolise certain nutrients and excrete toxins well. If your gut function is impaired, if there is inflammation in your gut (bloatedness, stomach cramps, gassiness, foul gas, irregular bowel movements) your fat loss is also impaired.


We are going to only touch upon insulin secretion for hormonal balance. 100g of carbs coming from simple sugars (e.g. Pop tarts) versus complex carbohydrates (e.g. Pumpkin) will initiate a very different kind of insulin secretion response in your body. For one, your blood sugar levels will shoot up much more quickly if you have simple sugars versus complex carbs. The pumpkin is filled with fibers and is going to digested much slower. This means your pancreas must secrete a large amount of insulin to get your blood sugar levels back to normal levels, usually, your blood sugar levels drop way below normal after sugar intake because of the large insulin response then taper back up to normal. These big ups and downs are the chief causes of “food coma” after lunch breaks. Slower release carbohydrates will generally be healthier for you than simple sugars.

High GI: Sugar – Low GI: Complex carbs



Finally, the toxic load and lack of micronutrients in highly processed foods will place extra stress on your liver and impair its function. (Think preservatives, sodium Nitrates and Sodium Nitrites, additives, MSG, Sodium Benzoate and Potassium Benzoate) Detox is separated into phase 1, phase 2 and phase 3. Phase 1 requires binding of vitamins and minerals to toxins, which then moves on to phase 2 in the liver where the combined toxins are bound to amino acids, then in phase 3, it is excreted through the urine.7


It depends.

IIFYM is not suitable for obese clients that are above 25%-30% body fat percentage, they are not insulin sensitive enough to handle simple sugars, they are inherently inflamed, they probably lack vital minerals and vitamins. Imagine a person with 35% body fat percentage, where do you think most of the nutrients will be shuttled to, fat cells or used to build muscle cells? Fat cells, of course, generally obese people have bad insulin sensitivity on top of bad nutrient partitioning. If it worsens it can lead to diabetes. Now compare the above to me, at 6.6% body fat and does weight lifting 5 times a week, where do you think most of the nutrients are shuttled to? IIFYM is suitable for people who are already insulin sensitive (usually people who have been weight training for a while), who are diligent in counting macronutrients and calories.

Most advocates of IIFYM choose to only portray the “junk” food portion of their diet to the public and boast that they are still getting leaner from it. It is inherently exciting to be rebellious and show extremes. It is the truth, people can get leaner from junk food, but they are probably eating healthy 80% of the time.

In my opinion, healthy eating most of the time should be everyone’s goal.

If your goal is the weekend gym warrior or getting a better than average beach body then, by all means, go for IIFYM. It allows you to enjoy the little pleasures in life, eating whatever you want while maintaining a relatively good physique and achieving fat loss. I understand there is a psychological benefit to IIFYM, where you are allowed semi-freedom with food choices which then curbs cravings and blowouts on “cheat” days.

If you are serious about getting the best physique possible (like me getting ready for a U175cm Men’s Physique competition in Hong Kong), if you have the self-determination, perseverance, and passion you can only attain the best physique possible by optimising every single part of your lifestyle for that one goal. It is ideal to eat food that causes less inflammatory response than junk food. It pays off immensely to be 100% efficient and optimising every aspect.

Having said all this though, a combination of both dieting method is probably more suitable to the general public who wants to be in shape and healthy, where you are eating 80% of your calories from healthy foods and 20% from junk food or whatever you want).

-Will Kong
Personal Trainer based in Hong Kong

  1. http://edition.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/
  2. https://www.ncbi.nlm.nih.gov/pubmed/21677052
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4579563/
  4. https://www.uaf.edu/files/olli/OLLI_15_chol_4_red.pdf
  5. http://mysupplementrd.com/fish-oils-omega-3-fatty-acids/cell-membranes-fatty-acids-inflammation/
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528021/
  7. http://www.lifestylebypoliquin.com/Lifestyle/StayHealthy/560/Detoxing_the_Right_Way.aspx

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