A recent study has challenged a popular belief that eating carbohydrates speeds up aging. In fact, the research suggests that eating the right kind of high-carb diet might actually help slow down or even reverse the aging process. The findings, published in the journal Aging Cell, indicate that for older adults, a short-term dietary change can make a measurable difference in their body’s biological age.

Your biological age is different from your chronological age, which is simply the number of years you have lived. Biological age reflects how well your body is functioning on the inside. Researchers often use it to predict future health risks more accurately. In this study, scientists from the University of Sydney used a method that analyzes specific health markers in the blood and body, like cholesterol levels and blood pressure, to calculate this biological age.

The experiment involved 104 healthy participants aged 65 to 75, who were randomly divided into four groups for four weeks. One group ate an omnivorous (杂食的), high-fat diet, which closely matched what many people normally eat. The other three groups tried different patterns: one was an omnivorous, high-carbohydrate plan; another was a semi-vegetarian, high-fat plan; and the last was a semi-vegetarian, high-carbohydrate plan. All meals were carefully provided and monitored to ensure they followed the diets exactly.

The results were surprising. Compared with the high-fat diet group, whose biological age remained almost unchanged, the omnivorous high-carbohydrate group showed a remarkable reduction, lowering their biological age by nearly four years on average. The groups on the semi-vegetarian diets also saw a trend toward a younger biological age. Critically, the carbohydrates they consumed were “good” complex carbs from whole, unprocessed foods, not refined sugars or white flour.

The scientists believe several mechanisms may explain these benefits. A diet rich in complex carbohydrates can lower chronic inflammation, a key driver of aging. It also improves metabolic health by stabilizing blood sugar and supports healthy gut bacteria (肠道菌群). This research strongly suggests that for lasting health, the quality of your carbohydrates is more important than simply reducing their quantity.

1.1. The underlined word “it” in Paragraph 2 refers to ________.

A the chronological age

B a person’s blood marker

C the biological age

D a future health risk

解析：选C。C词意指代题。根据第二段前两句“Biological age reflects how well your body is functioning on the inside. Researchers often use it to predict future health risks more accurately.”可知，“it”指代的是前一句的主语“Biological age”，即生物年龄，因此C项正确。A项“the chronological age”在下一句中被用来与生物年龄进行对比，并非“it”的指代对象；B项“a person’s blood marker”和D项“a future health risk”虽然都在该段中出现，但都是句子中的其他成分，与代词“it”没有指代关系。故选C。

2.2. How was the experiment mainly carried out?

A By studying a single group.

B By comparing different diets.

C By replacing the groups.

D By collecting expert views.

解析：选B。B推理判断题。根据第三段的“The experiment involved 104 healthy participants ..., who were randomly divided into four groups for four weeks. One group ate a ... diet. The other three groups tried different patterns...”可知，参与者被分成四组，分别实行不同的饮食方案，因此实验主要是通过比较四种不同饮食的效果来进行的，B项“By comparing different diets”符合这一推断。A项与“divided into four groups”相矛盾；C项和D项在文中均未提及，无法推出。故选B。

3.3. The author mentions “good” complex carbs to highlight ________.

A the dangers of refined sugar

B a hidden weakness of the study

C a popular method of cooking

D the reason for the positive effect

解析：选D。D观点态度题。第四段在陈述高碳水组生物年龄变年轻的结果后，用“Critically, the carbohydrates they consumed were ‘good’ complex carbs from whole, unprocessed foods, not refined sugars or white flour.”进行强调。作者在此处用Critically引出取得积极效果的核心因素，即“好”的复合碳水化合物是带来这一积极效果的关键原因。D项“the reason for the positive effect”正好对应这一意图。A项过度推断，作者提及精制糖仅为对比，并非旨在强调其危害；B项和C项在文中均无依据。故选D。

4.4. What would the scientists most likely recommend for a healthy diet?

A Cutting out all types of carbohydrates.

B Choosing more whole grains and vegetables.

C Stopping the intake of any high-fat foods.

D Following a strict semi-vegetarian diet.

解析：选B。B推理判断题。根据最后一段的结论“This research strongly suggests that ... the quality of your carbohydrates is more important than simply cutting them out.”以及前文对“好”碳水的定义（complex carbs from whole, unprocessed foods），可推断科学家会推荐人们选择来自天然食物的优质碳水化合物，B项“Choosing more whole grains and vegetables”与此建议最为吻合。A项 “彻底杜绝所有碳水化合物” 与原文观点完全相反；C项 “完全不摄入高脂食物”、D项 “严格遵循半素食饮食” 只是实验中的分组设定，属于片面解读，并非整体膳食建议。故选B。