Dr David McGrath

Spine Physician

MB BS (Hons) FAFOM, RACP, FAFMM
Master of Pain Medicine

Optimal Nutrition
Bottom Line:
We can conceptualise that, an optimal food composition intake exists.

This concept is an aknowledgement of a limit to nutitional replacement. If we need a certain amount of energy, coming from carbohydrates, protein and fat, an increase in one component , must reduce another. Quite simply
A+B+C=100%

For example,

ComponentsRatios	Ratio A	Ratio B	Ratio C
Carbohydrate	60	10	33 1/3
Fat	10	70	33 1/3
Protein	30	20	33 13

If all components had equal nutritional value, we should adopt "C". If carbohydrate had superior value, option "A", might be the better choice.
If we factor in nutritional value, we can appreciate the "optimal diet" concept more fully.
If we give some arbitary nutritional values to the energy components, not getting lost in detail, we have the following.

ComponentsRatios	Ratio A	Ratio B	Ratio C
Carbohydrate	60 by 0.1=6	10 by 0.1=1	33 1/3 by 0.1=3
Fat	10 by 0.3=3	70 by 0.3=21	33 1/3 by 0.3=10
Protein	30 by 0.5=15	20 by 0.5=10	33 1/3 by 0.5=17
Energy/Value	100%/24	100%/32	100%/30

Now, with our energy requirements met, we have different nutritional deliveries. The balanced diet "C" doesn't look so balanced. Option "B" is looking marginally better.
Of course, life is more complex than this.

1.The nutritional value is likely to be non linear. That is, the value is likely to be higher, at the lower intakes of these nutrients, and decrease or saturate at higher levels. For instance, we have a high value for smaller amounts of protein, which decreases, substantially, becoming a burden at higher levels (possibly to negative value). We have to get rid of amino acid degradation products. (nitrogen and sulpher )

2.There is also likely to be a minimum intake of the three components. For instance there are fat soluble vitamins requiring a minimum intake of fats. This is also true for proteins.There may also be a minimum for carbohydrate, but this is far from certain. This means the optimisation calculation has definite max/min boundaries.

3. If we assume, that only 25% of our calories can come from protein,before there is significant loss of value, this leaves 75% to be distributed to fat and carbohydrate. If there is a minimun carbohydrate intake of 10%, then 65% must be fat. (Fat having the higher nutritional value) This will optimise our nutrition.

ComponentsRatios	Ideal Ratio
Carbohydrate	10 by 0.1=1
Fat	65 by 0.3=20
Protein	25 by 0.5=13
EnergyValue	100% 34

An optimal diet may change with structural change, such as aging or simply adaption through a consistant dietary intake. We can in effect, get used to a sub-optimal nutrition, and enjoy good health. This does not detract from the the general idea, that an optimal nutrition might in reality exist, and we could be well served by finding and adopting such a diet.