Heavy weights will help increase strength and neuromuscular efficiency.
Lower weights (done for more reps) will help create muscle hypertrophy.
Both are necessary to achieve the phsyique you are after. However, if you are looking to lose weight, you will need to watch your diet and eliminate junk and some starches.
James 1:16-17 ESV
Do not be deceived, my beloved brothers. Every good gift and every perfect gift is from above, coming down from the Father of lights
With God's help...Mens sana in corpore sano