Regardless of your wishes, your lifts are heavily dependent on your bodyweight. Out of the Big Three, the squat and the bench press suffer the most when you start a diet.
Why? Because you can’t support a mountain on a pair of chicken legs.
During the bench press and the squat, your arms and respectively legs act as pillars supporting the heavy barbell. You can’t support a truly heavy weight on a pair of chicken legs and/or arms, can you? The bigger the house, the bigger the foundation.
Even if the weight you lose is mainly lard, your strength in the barbell movements will still suffer. Surprisingly to some, the extra fat assists in the fight against gravity by shorting the range of motion, protecting your joints, creating a form of cushioning and facilitating recovery (when you are fat, you are obviously well-fed).
As a result, dirty bulking has been a common strategy to increase a lift. Even in the past, some people were reaching insane bodyweight levels to improve their leverages.
A long time ago, Mr. Universe 1959 Bruce Randall decided to become a bulking soldier. He concluded that his overall strength is largely affected by his bodyweight. At one point, he weighed 380lbs. His squat at the time was 680lbs. According to his journal, weight added to his frame always resulted in weight added to the bar.
Note: Bruce Randall reached 400lbs, then cut down to 185lbs and eventually bulked up to 231lbs to win Mr. Universe 1959.
Who is going to fill the gap?
When you lose body fat, the range of motion of the bench press increases. Your chest is smaller, and therefore, the bar travels a greater distance. Even half an inch is an increase that will require more strength to push the weight up.
The same holds true for the squat which is also facilitated by body fat. Having a big gut can actually help you at the bottom of the squat because at that position the midsection is touching the inner upper legs. This creates more tension which equals more strength. When you are completely shredded there is less tension in that area.
In the video below, you can see the phenomenal 800lbs squat of Pat Mendes. Notice that at the bottom his gut goes between his legs and clashes against the inner thighs and the hip flexor area.
How can I avoid losing bench and squat strength on a cut?
The best way to keep something is to never lose it. To preserve your squat and bench press strength, you should keep lifting heavy when you’re on a diet. However, you will have to reduce the volume because of the lower caloric intake.
Note: The fatter you are when you start your diet, the more realistic it is to keep your strength. A person going from 25% BF to 20% BF will have an easier time preserving his strength compared to someone going from 12% BF to 7% BF.
What about the deadlift? Is it affected by weight loss as much as the squat and the bench?
The deadlift is not affected by bodyweight loss or gain as much as the bench and the squat. When you deadlift, you’re pulling the weight. Neither your arms nor your legs have to act as pillars. Instead, your whole body forms one super strong pillar/crane which can hold a lot of weight. That’s why a lot of skinny boys pull heavy. Conversely, you will almost never see someone with skinny arms and legs bench or squat serious weights.
Additionally, when you are on a diet, the range of motion during the deadlift does not increase. Actually, having a big gut could be an issue and many fat powerlifters experience problems getting into a proper position for the deadlift.