Fusioning atoms heavier than Lead consumes energy.
Not quite true, as the graph below shows. While Lead is the "stable" endpoint of a large number of decay chains involving heavy isotopes, the atomic number of lead (Z=82) is WAY too high for the claim your making; the nuclear force is not stabilizing enough to overcome the repulsion of that many protons.
Fission of Lead produces energy, IF you can find a favorable nuclear reaction kinetics to produce it. The chart below shows the break-even point, which is all the way down at the where the derivative of the binding energy per nucleon goes to zero, at Iron (Z=26.)
The corrected statement is:
Fissioning atoms lighter than Iron consumes energy.
Fusioning atoms heavier than Iron consumes energy.
