When people hear the term Unified Theory, some times called the Grand Unified Theory, or even "Theory of Everything," they probably think of it in terms of physics, where a Unified Theory, or single theory capable of defining the nature of the interrelationships among nuclear, electromagnetic, and gravitational forces, would reconcile seemingly incompatible aspects of various field theories to create a single comprehensive set of equations.

Such a theory could potentially unlock all the secrets of nature and the universe itself, or as theoretical physicist Michio Katu, puts it "an equation an inch long that would allow us to read the mind of God." That's how important unified theories can be. However, unified theories don't have to deal with such heady topics as physics or the nature of the universe itself, but can be applied to far more mundane topics, in this case nutrition.

Regardless of the topic, a unified theory, as sated above, seeks to explain seemingly incompatible aspects of various theories. In this article I attempt to unify seemingly incompatible or opposing views regarding nutrition, namely, what is probably the longest running debate in the nutritional sciences: calories vs. macro nutrients.

One school, I would say the 'old school' of nutrition, maintains weight loss or weight gain is all about calories, and "a calorie is a calorie," no matter the source (e.g., carbs, fats, or proteins). They base their position on various lines of evidence to come to that conclusion.

The other school, I would call more the 'new school' of thought on the issue, would state that gaining or losing weight is really about where the calories come from (e.g., carbs, fats, and proteins), and that dictates weight loss or weight gain. Meaning, they feel, the "calorie is a calorie" mantra of the old school is wrong. They too come to this conclusion using various lines of evidence.

This has been an ongoing debate between people in the field of nutrition, biology, physiology, and many other disciplines, for decades. The result of which has led to conflicting advice and a great deal of confusion by the general public, not to mention many medical professionals and other groups.

Before I go any further, two key points that are essential to understand about any unified theory:

A good unified theory is simple, concise, and understandable even to lay people. However, underneath, or behind that theory, is often a great deal of information that can take up many volumes of books. So, for me to outline all the information I have used to come to these conclusions, would take a large book, if not several and is far beyond the scope of this article. A unified theory is often proposed by some theorist before it can even be proven or fully supported by physical evidence. Over time, different lines of evidence, whether it be mathematical, physical, etc., supports the theory and thus solidifies that theory as being correct, or continued lines of evidence shows the theory needs to be revised or is simply incorrect. I feel there is now more than enough evidence at this point to give a unified theory of nutrition and continuing lines of evidence will continue (with some possible revisions) to solidify the theory as fact. "A calorie is a calorie"

The old school of nutrition, which often includes most nutritionists, is a calorie is a calorie when it comes to gaining or losing weight. That weight loss or weight gain is strictly a matter of "calories in, calories out." Translated, if you "burn" more calories than you take in, you will lose weight regardless of the calorie source and if you eat more calories than you burn off each day, you will gain weight, regardless of the calorie source.

This long held and accepted view of nutrition is based on the fact that protein and carbs contain approx 4 calories per gram and fat approximately 9 calories per gram and the source of those calories matters not. They base this on the many studies that finds if one reduces calories by X number each day, weight loss is the result and so it goes if you add X number of calories above what you use each day for gaining weight.

However, the "calories in calories out" mantra fails to take into account modern research that finds that fats, carbs, and proteins have very different effects on the metabolism via countless pathways, such as their effects on hormones (e.g., insulin, leptin, glucagon, etc), effects on hunger and appetite, thermic effects (heat production), effects on uncoupling proteins (UCPs), and 1000 other effects that could be mentioned.

Even worse, this school of thought fails to take into account the fact that even within a macro nutrient, they too can have different effects on metabolism. This school of thought ignores the ever mounting volume of studies that have found diets with different macro nutrient ratios with identical calorie intakes have different effects on body composition, cholesterol levels, oxidative stress, etc.

Translated, not only is the mantra "a calorie us a calorie" proven to be false, "all fats are created equal" or "protein is protein" is also incorrect. For example, we no know different fats (e.g. fish oils vs. saturated fats) have vastly different effects on metabolism and health in general, as we now know different carbohydrates have their own effects (e.g. high GI vs. low GI), as we know different proteins can have unique effects.

The "calories don't matter" school of thought
This school of thought will typically tell you that if you eat large amounts of some particular macro nutrient in their magic ratios, calories don't matter. For example, followers of ketogenic style diets that consist of high fat intakes and very low carbohydrate intakes (i.e., Atkins, etc.) often maintain calories don't matter in such a diet.

Others maintain if you eat very high protein intakes with very low fat and carbohydrate intakes, calories don't matter. Like the old school, this school fails to take into account the effects such diets have on various pathways and ignore the simple realities of human physiology, not to mention the laws of thermodynamics!

The reality is, although it's clear different macro nutrients in different amounts and ratios have different effects on weight loss, fat loss, and other metabolic effects, calories do matter. They always have and they always will. The data, and real world experience of millions of dieters, is quite clear on that reality.

The truth behind such diets is that they are often quite good at suppressing appetite and thus the person simply ends up eating fewer calories and losing weight. Also, the weight loss from such diets is often from water vs. fat, at least in the first few weeks. That's not to say people can't experience meaningful weight loss with some of these diets, but the effect comes from a reduction in calories vs. any magical effects often claimed by proponents of such diets.

Weight loss vs. fat loss!
This is where we get into the crux of the true debate and why the two schools of thought are not actually as far apart from one another as they appear to the untrained eye. What has become abundantly clear from the studies performed and real world evidence is that to lose weight we need to use more calories than we take in (via reducing calorie intake and or increasing exercise), but we know different diets have different effects on the metabolism, appetite, body composition, and other physiological variables...

Brink's Unified Theory of Nutrition
...Thus, this reality has led me to Brink's Unified Theory of Nutrition which states:

"Total calories dictates how much weight a person gains or loses; macro nutrient ratios dictates what a person gains or loses"

This seemingly simple statement allows people to understand the differences between the two schools of thought. For example, studies often find that two groups of people put on the same calorie intakes but very different ratios of carbs, fats, and proteins will lose different amounts of bodyfat and or lean body mass (i.e., muscle, bone, etc.).

Some studies find for example people on a higher protein lower carb diet lose approximately the same amount of weight as another group on a high carb lower protein diet, but the group on the higher protein diet lost more actual fat and less lean body mass (muscle). Or, some studies using the same calorie intakes but different macro nutrient intakes often find the higher protein diet may lose less actual weight than the higher carb lower protein diets, but the actual fat loss is higher in the higher protein low carb diets. This effect has also been seen in some studies that compared high fat/low carb vs. high carb/low fat diets. The effect is usually amplified if exercise is involved as one might expect.

Of course these effects are not found universally in all studies that examine the issue, but the bulk of the data is clear: diets containing different macro nutrient ratios do have different effects on human physiology even when calorie intakes are identical (1,2,3,4,5,6,7,8,9,10,11).

Or, as the authors of one recent study that looked at the issue concluded:

"Diets with identical energy contents can have different effects on leptin concentrations, energy expenditure, voluntary food intake, and nitrogen balance, suggesting that the physiologic adaptations to energy restriction can be modified by dietary composition."(12)

The point being, there are many studies confirming that the actual ratio of carbs, fats, and proteins in a given diet can effect what is actually lost (i.e., fat, muscle, bone, and water) and that total calories has the greatest effect on how much total weight is lost. Are you starting to see how my unified theory of nutrition combines the "calorie is a calorie" school with the "calories don't matter" school to help people make decisions about nutrition?

Knowing this, it becomes much easier for people to understand the seemingly conflicting diet and nutrition advice out there (of course this does not account for the down right unscientific and dangerous nutrition advice people are subjected to via bad books, TV, the 'net, and well meaning friends, but that's another article altogether).

Knowing the above information and keeping the Unified Theory of Nutrition in mind, leads us to some important and potentially useful conclusions:

An optimal diet designed to make a person lose fat and retain as much LBM as possible is not the same as a diet simply designed to lose weight. A nutrition program designed to create fat loss is not simply a reduced calorie version of a nutrition program designed to gain weight, and visa versa. Diets need to be designed with fat loss, NOT just weight loss, as the goal, but total calories can't be ignored. This is why the diets I design for people-or write about-for gaining or losing weight are not simply higher or lower calorie versions of the same diet. In short: diets plans I design for gaining LBM start with total calories and build macro nutrient ratios into the number of calories required. However, diets designed for fat loss (vs. weight loss!) start with the correct macro nutrient ratios that depend on variables such as amount of LBM the person carries vs. bodyfat percent , activity levels, etc., and figure out calories based on the proper macro nutrient ratios to achieve fat loss with a minimum loss of LBM. The actual ratio of macro nutrients can be quite different for both diets and even for individuals. Diets that give the same macro nutrient ratio to all people (e.g., 40/30/30, or 70,30,10, etc.) regardless of total calories, goals, activity levels, etc., will always be less than optimal. Optimal macro nutrient ratios can change with total calories and other variables. Perhaps most important, the unified theory explains why the focus on weight loss vs. fat loss by the vast majority of people, including most medical professionals, and the media, will always fail in the long run to deliver the results people want. Finally, the Universal Theory makes it clear that the optimal diet for losing fat, or gaining muscle, or what ever the goal, must account not only for total calories, but macro nutrient ratios that optimize metabolic effects and answer the questions: what effects will this diet have on appetite? What effects will this diet have on metabolic rate? What effects will this diet have on my lean body mass (LBM)? What effects will this diet have on hormones; both hormones that may improve or impede my goals? What effects will this diet have on (fill in the blank)?

Simply asking, "how much weight will I lose?" is the wrong question which will lead to the wrong answer. To get the optimal effects from your next diet, whether looking to gain weight or lose it, you must ask the right questions to get meaningful answers.

Asking the right questions will also help you avoid the pitfalls of unscientific poorly thought out diets which make promises they can't keep and go against what we know about human physiology and the very laws of physics!

There are of course many additional questions that can be asked and points that can be raised as it applies to the above, but those are some of the key issues that come to mind. Bottom line here is, if the diet you are following to either gain or loss weight does not address those issues and or questions, then you can count on being among the millions of disappointed people who don't receive the optimal results they had hoped for and have made yet another nutrition "guru" laugh all the way to the bank at your expense.

Any diet that claims calories don't matter, forget it. Any diet that tells you they have a magic ratio of foods, ignore it. Any diet that tells you any one food source is evil, it's a scam. Any diet that tells you it will work for all people all the time no matter the circumstances, throw it out or give it to someone you don't like!