How to create a diet: part 1


As you gathered form the title, the purpose of this article is to describe how a diet should be set up, or, at least how I think it should. The inspiration for this article came from the observation (personally, as well as overhearing conversations and scrolling through message boards) that many people are confused about how to set up a diet, whether it is a maintenance diet, fat loss diet or a mass gaining diet. This confusion among the lay public is unsurprising given the popularity of diets such as Barry Sears’s The Zone Diet (which centers around a 40:30:30 ratio of calories from carbohydrates, fat and protein, respectively), Weightwatchers (which focuses more on restricting the total quantity of food consumed by way of counting calories and “points”) and Dr. Atkins’ New Diet Revolution (a virtually zero carb, high fat, moderate protein diet).

There are literally hundreds of these types of diets that are almost exclusively intended for “weight loss”, or fat loss; the term that I prefer. Given the vast apparent difference between such diets, they all share a common theme; to trick you into eating less one way or another, whether this is by counting X, eliminating Y, combining such and such, not eating after a certain time, only eating certain things on specific days etc. Basically, success (i.e. fat loss) is achieved (at least in the short term) with such diets due to calorie restriction, whether the author admits to this fact or not. Another limitation of such diets is that they typically involve a one-size fits all approach with minimal, if any, consideration of individual differences in physiology, goal(s), dietary preferences etc. This is probably why some people swear by one type of diet over another and vice-versa. When in fact, neither are “better” per se. Rather, it is more likely that a favorable diet for a given individual "ticks more boxes", whether it be physiological, psychological or just integrates with their current lifestyle better.

Take The Zone Diet for instance, the amount of each macronutrient consumed at fixed macronutrient percentages is entirely dependent on the total calorie intake. For example, an 1800 kcal diet for an untrained female looking to lose fat would yield a macronutrient intake of 180:60:135 g of carbohydrate, fat and protein, respectively, which actually isn’t a bad starting point. Conversely, if a male endurance athlete with a daily energy requirement of 4000 kcal set their diet up in this manner, it would yield a macronutrient intake of 400:133:300 g of carbohydrate, fat and protein, respectively, which would be way to much protein and fat for their specific needs, and would compromise carbohydrate intake. Furthermore, attempting to stick to a specific macronutrient ratio on a meal-by-meal basis would become a full-time job, even for the most dedicated dieters (read bodybuilders!).


Estimating caloric and macronutrient requirements

The introduction has hopefully made a decent enough case for an individualised yet simplistic approach to setting up a diet, as opposed to having people gambling with a fad diet in the hope that it pays off. The framework that I use focuses on setting individual macronutrient requirements in four steps. After estimating total maintenance calories (1), I set protein (2), then fat (3) and let carbohydrate make up the remainder (4).


1. Estimating total energy expenditure

 When speaking of a maintenance caloric intake, what I really mean is a caloric intake that will more or less match energy expenditure, hence, maintain body mass. Total energy expenditure (TEE) consists of resting energy expenditure (REE) or basal metabolic rate (BMR), thermic effect of activity and the thermic effect of food (TEF).

While technically not the same thing, REE and BMR are often used interchangeably, and for all practical purposes, their differences are nothing to be concerned with when estimating caloric needs. REE/BMR pretty much represents the energy cost of sustaining life and is measured at rest in a fasted state. TEA includes the energy cost of all physical activity, both voluntary and involuntary (i.e. non-exercise activity thermogenesis). Non-exercise activity thermogenesis (NEAT), which makes up approximately 15-30% of TEA, includes things such as shivering, fidgeting and anything else that involves movement but isn’t really classed as exercise. TEF accounts for the average thermic effects of the macronutrients during digestion and roughly accounts for 10-15% of TEE. The TEFs for the individual macronutrients are: protein (25-30%), carbohydrate (6-8%), fat (2-3%).

As TEE is made up of the sum of REE/BMR, TEA and TEF, we have to be able to measure, or, at least estimate these individual components in order to work out an individual’s daily caloric requirements. Since most reading this won’t have access to a lab in order to measure REE/BMR, we have to estimate it using one of many prediction equations. The ‘Harris-Benedict’, ‘Mifflin-St Jeor’ and ‘Owen’ equations are the most popular ones in use, with the ‘Mifflin-St Jeor’ equation being the most reliable of the three. The equations are outlined below:



Men: 66 + (13.75 x weight) + (5 x height) - (6.76 x age) Women: 655 + (9.56 x weight) + (1.85 x height) - (4.68 x age)

Mifflin-St Jeor:

Men: (10 x weight) + (6.25 x height) - (5 x age) + 5 Women: (10 x weight) + (6.25 x height) - (5 x age) - 161


Men: 879 + (10.2 x weight) Women: 795 + (7.2 x weight).

What I use:

Men: 24.2 x weight. Women: 22 x weight


Where height is in centimeters, weight is in kilograms and age is in years.


I have also included the one I use with clients which is much simpler yet seems to produce values in line with the more complex equation. To illustrate this, I’ll run my stats through each equation and report by REE/BMR for each, where height = 181, weight = 78 and age = 23 (table 1.).


Table 1. My estimated REE/BMR based on popular equations.

Equation used

Estimated REE/BMR



Mifflin-St Jeor:




What I use:



As you can see from table 1, there is little difference between all the estimations. If anything, the Owen equation appears to be the odd one out in this instance. Given that the Harris-Benedict and Mifflin-St Joer equations take weight, height and age into account, there may be some discrepancies between those and my equation (which only takes body weight into account), at the extreme ranges of such values. However, for all commonly encountered/ realistic ranges in height, body weight and age, all four equations will produce very similar estimations.

Now that REE/BMR is taken care of, we need to factor in activity (TEA) and the thermic effect of food (TEF). Depending on the type, intensity, duration, and frequency of physical activity, energy needs for physical activity may vary from ~20% to 70% or more of REE/BMR. To estimate this energy need, you can multiply the previously estimated REE/BMR by and activity factor that is most similar to you your current exercise routine and lifestyle/job:

- Sedentary = BMR X 1.2 (little or no exercise, desk job)

- Lightly active = BMR X 1.375 (light exercise/sports 1-3 days/wk)

- Mod. active = BMR X 1.55 (moderate exercise/sports 3-5 days/wk)

- Very active = BMR X 1.725 (hard exercise/sports 6-7 days/wk)

- Extr. active = BMR X 1.9 (hard daily exercise/sports & physical job or 2X day training, e.g. marathon, contest etc.)

These various activity factors are quite generalised and therefore can have significant margins of error, thus negating the need to factor in 10-15% for the TEF. For this reason, an estimated maintenance caloric intake shouldn’t take precedence over real world changes in body mass or composition. Those who are aware of their maintenance needs (i.e. are weight stable for relatively long periods of time) and daily caloric intake needn’t bother with these estimations since they only serve to set a ball park estimate of maintenance caloric intake. It is also worth mentioning that elite endurance athletes (with very high training volumes) can easily exceed the highest activity factor outlined above. Using myself as an example, again, my activity levels are pretty moderate, so I'll use the  '1.55' activity factor. This equates to a total daily energy expenditure of roughly 2925 kcal. Now maintenance calorie needs are estimated (based on equations or real-world observations) we can go about filling this calorie allotment with varying proportions of macronutrients based on individual needs or preferences.

Continued here in part II