GENETICS
http://time.com/4501742/if-you-cant-
lose-weight-dont-blame-your-genes/
Mathers and his team wanted to see how strongly the genetic variant affected weight by studying how the gene might hinder or help people’s ability to lose weight. Would having the obesity-related gene make it harder for people to shed pounds than people without the weight-gaining form of the gene?
Among a group of nearly 9,000 people who were enrolled in 11 studies in which they agreed to genetic analysis and were randomly assigned to a variety of weight loss methods, including diet, exercise or drug-based therapies, Mathers found the answer was a surprising no.
...
“We found no evidence at all that FTO genotype affected weight loss,” says Mathers.
PREGNANCY
In a typical pregnancy, the mother will gain 20-25 lbs. Afterwards, through having the baby and losing the excess water weight, the mother will lose about 15 lbs. That leaves just 5-10 lbs afterwards which is a pretty trivial amount of weight to lose. Pregnancy is simply not a valid reason for staying overweight after the fact.
MEDICATION
I decided to look at antidepressants in particular because they are so varied and more or less representative of drugs as a whole. If there's something I've left out that is significantly different, let me know.
https://www.drweil.com/health-wellness/
body-mind-spirit/mental-health/
why-do-antidepressants-cause-weight-gain/
No one knows for sure why antidepressants do this. Some may trigger food cravings, particularly for carbohydrates. The drugs may also affect metabolism. It is also possible that when the antidepressants are effective, you become less depressed and regain your appetite (though this would only apply in cases where loss of appetite is a symptom of depression).
Let's break down these three theories.
In the case of food cravings, it would seem that the medication itself isn't preventing weight loss or causing weight gain, but rather that it allows for people with low self control to eat a lot more than they should. This is no excuse.
In the case of an affected metabolism, what would happen is that a person's body would try to conserve energy, making him or her feel lethargic and burn at most a few hundred calories fewer than normally. This is trivially solved by changing medications or by eating a few hundred calories less than one normally does. Still no excuse here.
The last case is of a rediscovered appetite. This is similar to the first in that weight gain resulting from this would be entirely in the control of the person taking the medication. Not being used to having a normal appetite is no excuse for eating everything in sight.
FOOD
We I've in a world where we have easy access to food that is significantly more calorie dense than it was, say, a hundred years ago. But guess what? Nobody is forcing you to eat any particular food! Being irresponsible about what you put into your body is no excuse for being fat! Even if you decide to eat calorie dense foods, all you have to do is not eat them at a surplus and you won't gain weight. It's no more complicated than that.
AGE
Age also affects BMR. “This is why you sometimes see people in their late 20s surprised at gaining a few pounds when they don’t feel like they have changed any of their eating habits,” Mohning says.
This is because after the age of 25 — which is the age where we stop growing bone — the metabolic rate goes down by 2 percent or more per decade, she says. So, in order to stay at the same weight without a change to your level of activity, you would have to cut your daily calories by the same amount.
Again, this is the same pattern as medications causing a slower metabolism. The answer is simply to eat less. At a 2% drop per decade, you'll likely never have to eat less than 80% of what you did in your 20s, but if you still really want to, all you have to do is get some exercise. Age is a small factor here and is no excuse for failing to maintain a healthy body, just like everything else.
Even if you become unable to exercise because of health conditions, nothing is forcing you to eat more than your base metabolic rate -- and it's very reasonable to get all of the nutrients you need while eating as little as 1500 calories per day.
In summary, nothing is stopping anyone from achieving an attractive (or at least presentable) weight. If you think I'm wrong, prove it instead of calling what I say "BS" because of what I can only assume are your own insecurities. Grow up and quit making excuses.
