Plastic surgeons can let out a sigh of relief -- it's not possible to gain weight just in your breasts. The only way to physically change their shape is through augmentation surgery. You gain weight proportionally all over your body according to your body shape, not just in one area. Although breasts are made up of a lot of fatty tissue that expands when you get heavier, your breasts are not the only place that increases in size when you eat a surplus of calories. No food or exercise can change this biological fact.
Breast Tissue 101
Your breasts contain fatty tissue as well as duct and lobule tissue, which assist with breast feeding. The ratio of these tissues is genetically determined. Some women have denser breasts, which contain less fat in relation to the other tissues. How much of each tissue you have is a matter of genetics. The only way to find out if your breasts are fatty or dense is through mammography. At certain times of the month, you may notice that your breasts feel fuller. This is a result of hormones related to menstruation -- not to an actual weight gain.
The fat tissue in the breasts is subcutaneous, which doesn't increase your risk of disease such as the risk caused by deep visceral fat, also known as belly fat. Subcutaneous fat may even have protective health properties, showed a study published in a 2009 issue of the Journals of Gerontology. People who stored more subcutaneous fat in their lower body, such as on their hips and thighs, were healthier than people of the same weight who stored the weight in the belly. When you gain weight, you can't decide whether those extra pounds are in the form of visceral or subcutaneous fat, though. And because there's no notable muscle in the breasts themselves -- only in the chest wall behind the breasts -- muscle gain isn't going to markedly change the size of your breasts.
Weight Gain and Your Breasts
The fatty tissue in your breasts contain cells called adipocytes, which swell up when you gain fat and shrink when you lose fat. When you gain weight, you don't actually increase the number of fat cells in your breast -- the fat cells that are there simply get larger. But so do other fat cells in your body; gaining weight doesn't change your overall shape. If you're built like a pear -- smaller on top and larger in the hips and buttocks -- you'll grow into a larger pear when you gain weight.
Although breast fat isn't unhealthy visceral fat, people with larger chests tend to carry more of this dangerous trunk fat. A study published in European Journal of Clinical Nutrition in 2011 showed that women with a large amount of breast fat also tended to have more mid-section -- or visceral -- fat. It's not the breast fat that raises these women's cardiometablic disease risks, but the high amount of visceral fat; but the two seem to occur on the same type of body shape.
Yo-Yo Dieting Has Negative Effects on Your Breasts
Trying to gain weight only in your breasts can have implications on their perkiness. When you gain weight only to find it doesn't go to your desired area, and then go on a quick, fad diet to lose weight -- you do damage to the collagen and elastin that make your breasts firm and lifted. These supportive proteins become overstressed and stretched out, so you end up with a saggy chest -- especially if you make this a repetitive habit. If you do need to lose weight, do so gradually so the tissue can adapt to your changing body. You'll still experience the natural sagging that occurs with age and breastfeeding, but you won't contribute to this with unhealthy weight manipulations.
Breasts at Risk
Gaining too much weight can have a negative effect on your breast health, especially after menopause. Obese women are more likely to develop breast cancer later in life. The expanded fat tissue abnormally affects your hormone production, which raises your cancer risk.
The only way to expand your breasts is with surgical intervention, which carries its own risks. The implants don't last forever and may need to be removed, which causes permanent changes to your natural breasts -- including deflation, wrinkling and scarring. Complications can also occur during implantation and sometimes cause results that are irreversible, such as asymmetry and pain. You may need to undergo periodic MRI exams, especially if you have silicone-filled implants, to ensure you don't experience a rupture.