Energy Pie

The primary purpose of food is to provide energy to power your body. Food energy comes from carbohydrate, protein and fat. These are called macronutrients. All of your calories for the day derive from these three energy sources (and perhaps alcohol). This seems simple enough but the interaction between the macronutrients is more complex and often misunderstood. The following discussion uses the concept of your daily “energy pie” to explain what it really means to eat “low carb”, “low fat” or “high protein”.

We first need to establish a measuring unit for how much energy we get from each of the three macronutrients. Grams of each per day will not do because fat has more than twice the calories per gram as either protein or carbohydrate. The number of calories we get from each source is better but it going to be hard to compare different diets and different people because the daily calorie intakes will vary enormously. Therefore, we shall measure each macronutrient in terms of its percentage contribution to daily calorie intake. The percentage of calories from carbohydrate, protein and fat can be applied to a whole day’s food intake, a long term diet or even a single food item.

Typical Western Diet


This pie illustrates a typical Western diet similar to that eaten by most Australians.

The pie shows the proportion of calories from each source not the total number of calories. If you ate two serves of everything that day the pie would still look the same.


Let us consider what happens when you change one part of the pie. Remember that the updated daily energy pie represents the proportion of calories from each macronutrient so it’s still a whole pie that adds up to 100% even if your total day’s calorie intake is bigger or smaller. The following pie illustrates what happens when you decrease the amount of carbohydrate in your day:

Low Carbohydrate


Note that the proportion of daily calories from protein and fat is much higher as a result of the reduction in carbohydrate. You cannot change one macronutrient without a counter balancing effect on the other two. It’s like a seesaw with three arms: when one arm goes down, one or both of the other two must go up.


The low carbohydrate pie is also a high fat, high protein pie. Even the most “carbophobic” dieters know that eating more fat is not healthy so let’s make the next pie represent a low carb, low fat diet:

Low carb and low fat


This pie has a dangerously high protein content, like some weight loss meal replacement drinks that have “use under medical supervision” on the label. Hopefully the medical supervisor will advise against their use.



The next pie is typical of a so called “low fat” diet that is recommended for people with heart disease:

Typical "low fat"


Although the fat content is lower than the usual Western diet, it is still very high by international standards, and the protein content is higher because of the emphasis on low fat meat and dairy products.



The final pie represents a whole foods plant based diet consisting mainly of whole grains, vegetables, legumes and fruit – this is a high carbohydrate diet:

High Carbohydrate


The protein content of 12% exceeds the recommended intake of 10% of calories.

We consider that this balance of macronutrients is close to optimal for preventing obesity, diabetes and heart disease and keeping you feeling your best.


There are alternative whole foods plant based diets that include a lot of nuts and seeds giving them a higher fat content, higher protein content and lower carbohydrate content.

Lack of appreciation of the counterbalancing effects of carbohydrates, proteins and fats can result in your diet not being what you think it is. For example, an endurance athlete trying to eat a high carbohydrate diet to maximise performance may unwittingly add cheese (fat and protein) and margarine (fat) to their pasta and bread. The energy pie would then have bigger fat and protein sections and therefore the carbohydrate section shrinks from high to moderate.

If only the Australian community had a better understanding of “the daily energy pie” then people would realise that their “low carb” diets are actually dangerously high in animal protein and fats.

For links to further information on low carbohydrate diets go to the Low carbohydrate diets page.

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