Which of the following best describes our understanding of how genetics influences weight?

• A. A person's weight is largely determined by whether they carry more set-point genes, or thrifty genes.
• B. Most cases of obesity can be linked to one or two genes that have a large effect.
• C. The large increase in obesity rates in recent years is some of the strongest evidence that exists for the set-point theory of weight.
• D. In most cases, the genetic influence on a person's weight involves hundreds of genes all with small effect.

Answer: (D)

Verified step by step guidance

1. Understand the context of the question: The problem is asking about the role of genetics in influencing weight, which is a key topic in nutrition and health sciences.
2. Review the provided answer choices and identify the key concepts: The options mention terms like 'set-point genes,' 'thrifty genes,' and 'genetic influence,' which are important to understand in the context of weight regulation.
3. Clarify the correct concept: Research shows that weight is influenced by a combination of genetic and environmental factors. In most cases, genetics involves hundreds of genes, each contributing a small effect, rather than one or two genes with a large effect.
4. Eliminate incorrect options: For example, the idea that obesity is linked to one or two genes with a large effect is incorrect because obesity is a polygenic trait. Similarly, the set-point theory and thrifty gene hypothesis are older theories that do not fully explain the complexity of weight regulation.
5. Conclude with the correct understanding: The correct answer is that the genetic influence on weight involves hundreds of genes, each with a small effect, which aligns with current scientific evidence in the field of nutrition and genetics.