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Energy Density

Today I want to cover another fundamental aspect of nutrition that is somewhat easy to confuse.  That concept is referred to as energy density.  Energy density integrates, in a fashion, the concepts of calories, nutrients and food intake (a topic discussed in detail in the article Calories, Nutrients or Food?).

First I want to define energy density before looking at some examples that will hopefully make the concept a bit more clear.  Finally, I’ll look at applications of the energy density concept in terms of dieting, weight gain, etc.


What is Energy Density?

Conceptually, energy density refers to how many calories are found in a given weight or volume or food.  Ok, what does that mean. Let’s say that you have 1 gram of each of the three macronutrients which are protein, carbohydrates and fat.  We know that these are given calorie values of 4 cal/g for protein and carbs and 9 cal/g for fat.  Clearly, in this simple example, fat has over twice the energy density of either carbs or fat (9 cal in one gram vs. 4 cal in one gram).

This basic fact is generally interpreted one of two ways depending on whether a given … Read More

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Diet Percentages: Part 2

Now that you know how to do the calculations from Diet Percentages: Part 1, in this article I want to talk about some of the problems inherent in setting up diets based on percentages.

Reviewing basic physiology

On a day to day basis, your body has certain nutrient requirements, a topic which is discussed in detail elsewhere in this book. As described in those chapters, those nutrient requirements are generally related to how much you weigh (or how much lean body mass you have). There are a few exceptions, places where the requirements for a given nutrient are absolute which I’ll mention when necessary.

For example, at any given moment, nearly all of the tissues in your body are utilizing some amount of protein for various processes. Your liver, your kidneys, your muscles, your fat cells, your gut are all using protein for protein synthesis and energy needs. Meaning that the more of those tissues you have, the more protein you need; the less of those tissues you have the less protein that you need.

The same goes for carbohydrate and fat. Your body is using energy at some rate (set by your metabolic rate which is fundamentally related … Read More

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Diet Percentages: Part 1

Commonly, when you see diet plans laid out, the intake of the various macronutrients (protein, carbohydrate, fat) is presented in terms of percentages of total caloric intake. So you might see a diet which was 60% carbohydrates, 30% protein and 10% fat or some other set of percentages. Or you’ll see recommendations that ‘…athletes only need 15% of their calories from protein.’ or ‘don’t eat more than 30% of your total calories from fat’, that sort of thing.

In this article, I want to teach readers what these percentages mean and how to use them (if you so desire) either analyze a given diet, set up a diet, or figure out what a food label means.

A quick recap on calories

In a previous chapter I gave you the caloric content of the various macronutrients. To save you needless paging, I’ll review them here.

  • Protein: 4 calories/gram
  • Carbohydrate: 4 calories/gram
  • Fat: 9 calories/gram
  • Alcohol: 7 calories per gra

Calculating percentages

With the above values in hand, and using some basic math, we can do several different operations in terms of diet and food analysis. Let’s look at each one in turn. I’ll give examples but don’t read too much … Read More

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Carbohydrate and Fat Controversies: Part 2

In Carbohydrate and Fat Controversies: Part 1, I begun an examination of the argument over carbohydrate and fat intakes in the human diet, explaining that, contrary to popular argument, most extremist stances in this debate are incorrect. In Part 2, I want to continue addressing the issue by looking at both sides of the debate.

Examining Both Sides of the Debate

As noted, the usual argument goes that high-fat diets cause high-cholesterol, heart disease, cancer, obesity and the rest, as evidenced by the high incidence of those disease in modern diets (which are typically high in fat). But that’s a questionable conclusion to draw.

Modern diets are also high in carbohydrates (and mainly the highly refined, high GI, low-fiber stuff that the body often doesn’t handle well), low in fruits and vegetables, and generally contain the wrong types of fats (an excess of saturated and trans fats with insufficient amounts of healthy fats). Such an intake is typically coupled with inactivity, the folks eating them tend to be overweight/obese, smoking and alcohol play a role, etc. That is, there are a number of inter-related factors at work here.

Pinning the blame entirely on fat intake or expecting only a … Read More

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Carbohydrate and Fat Controversies: Part 1

Although there are still many Protein Controversies (usually regarding kidney health, bone health, etc.), nowhere in the dietary world is there quite as much controversy as over carbohydrate versus fat intakes.

In this article, I want to look at carbohydrate and fat intake in terms of the various arguments and debates that tend to surround them.

The main controversy here revolves around what amounts of carbohydrates and/or fat are ideal, healthy, recommended, etc. and that’s what I’ll focus on. I’m not going to deal with body composition explicitly in this article, I’ll save that for another day.

Two (or Three) Dietary Camps

Generally, folks fall into one of two camps regarding whether they think carbohydrates or fats are good or bad. For a couple of decades now, the mainstream of dietary advice has been more or less stuck in the mindset of ‘fat is evil and ‘carbohydrate is good’.

Various attempts to promote so-called ‘high-fat’ or ‘low-carb’ diets have usually been shot down as fads although there is increasing research evidence that, at least for some individuals (usually those with insulin resistance) higher fat intakes and lowered carbohydrates may be both beneficial and preferred.

However, for the most part, I’d … Read More