**Core Concept**
Nutritional surveillance refers to the systematic collection, analysis, and interpretation of data on dietary habits and nutritional status of populations to identify and address nutritional problems. This concept is crucial in public health and preventive medicine, enabling healthcare professionals to develop targeted interventions and policies to promote healthy eating habits and prevent nutritional-related diseases.

**Why the Correct Answer is Right**
Nutritional surveillance involves monitoring and evaluation of dietary intake, anthropometric measurements, and biochemical indices to assess the nutritional status of populations. This process helps in identifying areas of concern, such as micronutrient deficiencies, and informing policy decisions to address these issues. For instance, surveillance data may indicate a high prevalence of iron deficiency anemia in a particular region, prompting public health initiatives to improve iron intake through dietary recommendations and supplementation programs.

**Why Each Wrong Option is Incorrect**
**Option A:** This option may be a true statement, but without more context, it's difficult to evaluate its accuracy.
**Option B:** This option may be a true statement, but without more context, it's difficult to evaluate its accuracy.
**Option C:** This option may be a true statement, but without more context, it's difficult to evaluate its accuracy.
**Option D:** This option is likely incorrect because nutritional surveillance is not solely focused on detecting nutritional deficiencies but also on promoting healthy eating habits and preventing nutritional-related diseases.

**Clinical Pearl / High-Yield Fact**
A key aspect of nutritional surveillance is the use of biomarkers, such as hemoglobin levels and serum ferritin concentrations, to assess micronutrient status. Healthcare professionals should be aware of the limitations and potential biases of these biomarkers and consider multiple indicators when evaluating nutritional status.

**Correct Answer: D. Nutritional surveillance is not solely focused on detecting nutritional deficiencies but also on promoting healthy eating habits and preventing nutritional-related diseases.**