Here is a picture of some hunter-gatherers taken in the late 1930s. They are aboriginal australians. Notice the 6 pack abs even on the old man. I'm guessing they didn't get that way by pumping iron at the gym all day.
A few things...I had gastric bypass (RNY). I use to be 300 pounds...I got down to 187, I'm now about 220. When you get the bypass, the doctor usually cuts the vagus nerve in the stomach. This plus they separate the bottom of the stomach (which releases the ghrelin hormone) that causes hunger. I feel no hunger. I will get that "not full" feeling and can sense when my blood sugar level is dropping...But I feel no hunger. This make it much easier to lose weight. The problem with me, is I will graze through out the day. I'll eat 50 times a day...Many times it will be 3 nuts and a few Cheerios. The problem is I will eat the wrong foods and won't commit to a regular exercise program. I live in California and like to ride my bike. But, with the rains and cold, it's not conducive to ride. I know what to do...I just don't carry it out. During WWII in England, they "knew" they had a problem. Many middle aged men and women would have to walk 4 or 5 miles to town to get their food and essentials. The heart attack rate would rise quickly!! The exact opposite happened...
i've religiously logged my diet and exercise for about 10 months. I kind of changed how I eat, but not that much. I did add a lot of exercise. Every pound of weight I have lost has been due to exercise and almost 100% of the weight has been fat (as measured by body fat calculations done by my trainer).