Study Probes How Diet Affects Ageing and Longevity

The study revealed that caloric restriction—eating fewer calories—had a greater impact on lifespan than intermittent fasting or time-restricted feeding.

The food you eat doesn't just impact your daily life but also plays a big role in how you age and how long you live. Your diet, along with other lifestyle factors, is crucial for healthy ageing and living a longer life. Caloric restriction (eating fewer calories) and intermittent fasting (limiting the time you eat each day) have attracted a lot of attention for their potential to extend a healthy life. It's important to identify the most effective forms of dietary restriction to develop strategies that can improve human health and longevity.

Breakthrough Study on Diet and Longevity

A recent, highly anticipated study published in Nature by scientists at the Jackson Laboratory (JAX) explored the relationship between diet and lifespan. The study, one of the most comprehensive to date, tracked the health and longevity of nearly 1,000 mice fed different diets. Each mouse was genetically distinct, which made the results more relevant to the diversity of the human population.

The researchers aimed to answer long-standing questions about how eating less food or eating less often can help animals, and potentially humans, live longer. The study's design allowed scientists to investigate which dietary approaches were most effective, shedding light on the best ways to implement these strategies for humans.

Key Findings: Caloric Restriction vs. Intermittent Fasting

The study revealed that caloric restriction—eating fewer calories—had a greater impact on lifespan than intermittent fasting or time-restricted feeding. Mice on very low-calorie diets generally lived longer, regardless of their body fat or glucose levels, which are usually considered markers of metabolic health and ageing.

Interestingly, the mice that lived the longest on these restrictive diets were those that lost the least weight. Those who experienced significant weight loss tended to have low energy, compromised immune systems, and shorter lifespans. This finding suggests that while reducing calorie intake can extend life, excessive weight loss may have negative effects on overall health, including immune and reproductive function.

Implications for Human Longevity

While the study was conducted on mice, it offers important insights that could help shape dietary recommendations for humans. The findings suggest that diets low in calories but rich in nutrients—particularly those with a higher proportion of carbohydrates from plant sources and limited consumption of dairy, fish, meat, and processed/refined foods—may support longevity.

Specific foods may also play a role in extending lifespan. Nutrient-dense options such as garlic, purple sweet potatoes, soybeans, and olive oil are believed to have life-extending properties. These foods are rich in antioxidants, healthy fats, and other compounds that support cellular health and combat the effects of ageing.

The Role of Eating Habits in Longevity

In addition to the types of food consumed, eating behaviours are also important for longevity. Practices such as mindful eating (being attentive to hunger and fullness cues), social dining (sharing meals with others), and avoiding overeating have been linked to longer life. Mindful eating helps prevent overconsumption and promotes a balanced approach to food intake, while social dining has emotional and psychological benefits that can contribute to overall well-being.

The Gut Microbiome and Ageing

Another area of growing interest is the role of the microbiome—the community of bacteria in the gut—in the ageing process. Research suggests that the microbiome influences many aspects of health, including digestion, metabolism, and immune function, all of which are important for healthy ageing. A diet rich in fibre, fruits, vegetables, and fermented foods can support a healthy microbiome, potentially contributing to a longer lifespan.