She said more research is needed in this area to determine when weight gain becomes a concern, because people will typically gain weight as they get older.
"We don't know how much weight should people gain over a lifetime once they're an adult," said Ikeda.
Fact or Myth? If Your Parents Are Overweight, You Will Be Too
Answer: Myth -- With a Healthy Dose of Truth
"That has been shown to hold some truth," said Politi.
Weight as an adult has been shown to have a strong genetic component, although lifestyle habits you are brought up with also play a role.
"It's probably what your parents feed you and the level of activity you do as a family," she said. "There's definitely a genetic contribution, but it's not the only one."
Politi notes that while human genes have not changed drastically in recent years, there is an epidemic of obesity because we are more sedentary and eating more calories.
"If you're vigilant with your food choices and you exercise, I don't think you're going to gain weight, or at least you're not going to gain as much weight as someone who is not careful."
By working out properly, weight can be held in check. "Nothing is preordained," said Ikeda.
However, she noted, weight alone does not determine your health.
"Certainly your risk or chances of being overweight are greatly increased if your parents are overweight, and there are plenty of studies to back that up," she said.
However, Ikeda added, "If you have large parents, your chances of being big are increased, but that doesn't mean you can't live a happy healthy life."
By exercising, she said, you can live healthily even if you carry more weight than others.
Fact or Myth? Physically Fit=Healthy
"They're closely linked, but they're not the same thing," said Ikeda.
She notes people not considered "healthy" can live well through exercise and exercise can help them manage chronic diseases they may have.
For example, Ikeda said, someone with Type 1 diabetes or someone who has recently suffered a heart attack or stroke can better manage their illness if they are in good shape.
"It certainly helps in terms of handling any kind of disease or illness that you have," she said.
Politi notes that many people stay thin in their 20s and 30s without exercising, but beyond that most need a workout regimen, unless they are "blessed by great genes."
Even then, she said, thin people can benefit from exercise, which combats physical conditions as well as mental conditions, like depression.
"Studies have shown that exercise helps reduce the risk of heart disease, helps resist the risk of cancer."
Fact or Myth? Women Who Weight Train Bulk Up
"For a woman to bulk up, it takes a tremendous amount of weight training, more so than men," said Ho.
Men who work out a lot may bulk up, but that is because of the anabolic testosterone that men's bodies produce. The average woman, therefore, should not be concerned.
Ho noted that women who do strength training may gain some mass, but "they will lose an equivalent amount of mass, or bulk if you will, in fat."
Effectively, he said, they are "trading fat for muscle. That extra muscle mass will help them burn the extra fat."
Some women do bulk up after weight training, Ho said, but they have often done something to alter their body chemistry.
Endress noted that women typically use lighter weights when doing strength training, and that alone will not lead to bulking up.