Special Diets

The body’s circadian clock plays a critical role in regulating metabolism, and disruption of natural rhythms has been associated with high cholesterol levels and other signs of poor metabolic health.¹⁰ Shift work and other causes of short nighttime sleep, as well as variability in sleep and activity patterns from day to day, have been found to correlate with higher cholesterol levels.^{11, 12} Observational evidence indicates those with a preference for evening activity, including eating, have worse metabolic health, including higher cholesterol levels.^{13, 14, 15}

Compared with those who routinely skip breakfast, habitual breakfast eaters have been noted to have better lipid profiles and lower cardiovascular risk.¹⁶ In a crossover-design clinical trial, 12 healthy participants ate a controlled diet comprised of three meals and two snacks during two eight-week phases: in the first phase, eating was restricted to the hours of 8AM–7PM, but in the second phase, eating was delayed until noon and ended at 11PM. A number of other metabolic markers, including total cholesterol levels, improved after the daytime eating phase and worsened during the delayed eating phase of the trial.¹⁷ In addition, a habit of eating smaller amounts more frequently during the day has been associated with lower cholesterol levels.¹⁸

Exercise and a physically active lifestyle have been found in multiple randomized controlled trials to increase protective HDL-cholesterol while decreasing heart disease-related triglyceride, LDL-cholesterol, and total cholesterol levels.^{19, 20} Even low-intensity exercise such as walking and Tai Chi can raise HDL-cholesterol levels, while more rigorous exercise may be needed to lower LDL-cholesterol levels.^{21, 22, 23} Importantly, weight gain appears to nullify the positive effects of exercise on lipid levels.²⁴ Some evidence suggests evening exercise is more effective than morning exercise for improving cholesterol levels.²⁵ Physical activity has the additional advantage of lowering risks of heart disease, type 2 diabetes, depression, anxiety, cancer, and myriad other chronic conditions.²⁶

Smoking impairs lipid metabolism and is linked to increased total, LDL-, and non-HDL-cholesterol levels, as well as lower HDL-cholesterol levels. Even secondhand smoke exposure has negative impacts on cholesterol levels, especially in children.²⁷ Furthermore, smoking is a major contributor to heart disease. Quitting smoking can result in improvement in lipid levels and is an important strategy for decreasing cardiovascular risk in people with high cholesterol levels.²⁸

Psychological factors such as anxiety, depression, distress, anger, and hostility have been shown to contribute to heart disease risk in both men and women.²⁹ On the other hand, optimism, conscientiousness, openness to experience, and curiosity have been found to reduce cardiovascular risk.³⁰ Some, but not all, research indicates yoga and mindfulness may improve markers of cardiovascular health, including cholesterol levels.^{31, 32, 33}