A high-quality source of protein like eggs sounds like a logical pairing with resistance training to build lean body mass, but may lead some to question what effect eggs may have on cardiovascular risk factors, like blood lipids (Clayton, 2015).

To answer this question, 12 healthy young men and women ages 18-35 years of age agreed to participate in a supervised 3 times/week resistance training study conducted over 12-weeks. Training focused on major muscles of the arms, chest, back, deltoids, and legs.

Participants were divided into two groups with half assigned to eat egg-based breakfasts (EBB) containing 2 eggs and the other half assigned to eat a breakfast containing a 9 cm bagel (BBB). Both groups self-selected breakfasts from isoenergetic breakfast menus, however the macronutrient distribution differed between groups. The egg-based menus were 43% energy from carbohydrate, 25% protein energy, and 32% fat energy. The bagel breakfast was 68% energy from carbohydrate, 17% protein energy, and 15% fat energy.

Body weight, percentage body fat and fat-free mass were stable throughout the 12-week study. Strength improved in both groups.

The group eating 2 eggs/day at breakfast (contributing about 372 mg cholesterol/day) showed reduced plasma triglycerides. Blood cholesterol was unchanged in both egg and bagel breakfast groups, including LDL-cholesterol, HDL-cholesterol, total cholesterol:HDL-C ratio, and LDL-C:HDL-C. Lack of effect of higher dietary cholesterol is consistent with broader evidence summarized in the 2013 American Heart Association/American College Cardiology lifestyle guidelines expert panel recognizing that moderate dietary cholesterol is only inconsistently related to LDL-C and that managing dietary saturated and trans fats are the primary goals (Eckle, 2014).

One transient change was observed among the bagel breakfast group (BBB).

[A] significant decrease (p<0.05) in insulin sensitivity was observed for the BBB [bagel based breakfast] group from baseline to 6 weeks, which returned to baseline levels at the 12-week time point.

This could reflect an adaptation to a higher carbohydrate breakfast, or could be a spurious statistical finding from testing multiple outcomes in the study.

The researchers noted:

Interestingly, the daily breakfast including 2 whole eggs when combined with regular resistance training did not adversely affect plasma lipids, glucose, or insulin, despite a significant (p<0.05) increase in dietary cholesterol from baseline to 12 weeks…

Results suggest that

incorporating 2 eggs per day into the diet of healthy adults who participate in regular resistance training will not adversely influence lipid profiles or glucose handling.

In fact, a transient modest improvement in a calculated insulin sensitivity index was observed in the EBB [egg-based breakfast] group.

Overall, this study shows that egg breakfasts are metabolically neutral when paired with a 3 day per week resistance training program among healthy adults.

Source: Egg Nutrition Center (ENC).