Someone unfamiliar with the RELIED 500 Cal Plan may mistakenly believe that it recommends a daily intake of 500 Calories (which a 500 Cal plan, if it existed, would recommend).
In fact:
1) The RELIED 500 Cal is based on the production of a deficit of 500 Calories per day as suggested by Mark Bricklin (1979) in his book “Lose Weight Naturally” published by Rodale Press, Emmaus, Pennsylvania.
2) The deficit should be arrived at by the production of:
a) A Raised expenditure (RE) of energy of 200 Calories and
b) A Lowered intake of energy (LI) of 300 Calories
[Note: This quantity of energy represents the 300 in Mark Bricklin’s “Natural 300 Plan”]

Mark Bricklin’s quantities (figures) are a good reference/starting point.
However, as stated in earlier entries of the present series, the RELIED 500 Cal Plan allows for flexibility with regards to actual quantities concerning raised energy expenditure (RE) and lowered energy intake (LI).
[Please see previous entries, more especially “Obesity simplex (primary obesity): Facing up to its reality” and “Practical aspects of the RELIED 500 Cal Plan (A concise user’s manual)”].

Moreover, as the body weight changes more adjustments can and need be made but it is recommended that the RE (raised expenditure) remains a permanent feature.
This is essential for general health reasons, and more especially, if one wanted to maintain the newly acquired ‘desired’ weight over a significant (meaningful) period of time (if not on a permanent basis).
[Note: The RE should be quantified on an individual (personalised) basis (please read previous entries, more especially: “Walking as a means of producing a net expenditure of 200 Calories].

Thus one difference between the RELIED 500 Cal Plan and the ‘Natural 300 Plan’ relates to methodology (and also, possibly emphasis).
Everyone can quantify their lowered energy intake (LI) by simply referring to the energy contents of foods left out (not taken in).
However, to quantify raised energy expenditure (RE) one needs to take a personalised (individual) approach.
[Note: RE is deemed to be more important than LI, although both are required].

Ultimately and ideally the activity or activities producing the RE (raised expenditure) should be geared (adapted) to:
3) Improving physical fitness (cardio-respiratory endurance, muscle strength and endurance, and flexibility)
4) Maintaining lean body tissue (skeletal muscle).

500 Cal Plan
Either the plan does not exist or no one should be on it.