1. Etiology

   • A human has a smell because there are bacteria in his body. Bacteria thrive in damp areas, and when a person sweats, he creates an environment in which bacteria can grow. Body odor is generally the smell of bacteria growing on the skin, because sweat itself has no smell. That is why body odor is stronger in damp places: under the armpits, between toes and the groin area. Males usually have stronger body odor than women because of the androgen hormone and a certain kind of bacteria in the skin. While some females also have these bacteria, their lower androgen production mixed with progesterone and estrogen do not produce the same level of body odor. In most cases of body odor, improved hygiene eliminates the problem, but there are times when the cause is hormonal and a medical situation exists.

   Hormones and Diet

   • Hormones play important roles in our bodies and lives. Hormones make us grow, and help our internal organs and metabolism function properly. Any snag and our bodies suffer disorders ranging from cretinism to mood swings, infertility to excessive stress, hyperthyroidism to extreme sex drive. Diet and severe eating disorders such as bulimia and anorexia nervosa may force the body to eliminate a great deal of waste to balance the body metabolism. In doing so, perspiration can be excessive and body odor will result.

   Environment

   • There are substances around us that we inadvertently ingest that influence our metabolism. Traces of heavy metals, chemicals from herbicides, pesticides in plants, poisons from plastic food containers and substances from the water we drink and the air we breathe may negatively affect our hormonal balance. The ordinary tin can in processed foods has been reported, for example, to infuse estrogen-like hormones in the body, causing the body to reduce production of the estrogen.

   Stress and Menopause

   • Whether caused by physiological, emotional or environmental causes, stress can wreak havoc with the adrenaline gland, causing hot flashes, allergies, chronic fatigue, insomnia and excessive sweating. The normal levels of progesterone and estrogen are whacked out of balance by menopause, so during hot flashes of menopause, inordinate sweating may occur, resulting in body odor.

   Source of Hormones

   • Hormones are produced by glands, so if you don’t know the source of your hormone imbalance but suspect you have one, see a doctor as hormone and glandular problems can be serious and expose underlying health problems.

Summary: Paradoxical as it sounds, new research shows that a better body image could actually help you lose more body weight. In other words, accepting your body as it is and spending less time thinking about it is the best way to live a leaner, healthier lifestyle.

We’re bombarded with images of unattainable, unrealistic, and unhealthy beauty. Start with an average model, who has a BMI of 16.5. Add lots of computer software and hours of editing. You end up with a distorted, imaginary, arguably non-human view of what purports to be a “normal” and beautiful body.

For some perspective, at my height of 5’8″ (173 cm), I would have to weigh 107.5 lb to have a BMI of 16.5. Since my normal weight is about 140 lb, I would have to lose all my body fat plus nearly 10 pounds of lean body tissue.

Then of course, I’d be airbrushed into oblivion. (To get an idea what is possible with digital enhancement, take a look at a weight loss session done with Adobe Photoshop software).

But here’s the paradox. Bizarrely, impossibly thin images are all around us. Yet more people are overweight and obese than ever before. Seems odd. You’d think that having more pressure would push people into the direction of losing weight, but the opposite is happening instead. Why?

Being a biologist I like to think that biology matters and can explain things more than, say, squishy things like feelings and perceptions. So I might have argued that weight loss was simply energy in (food) versus energy out (movement).

Looks like us geeks might have been a little simplistic.

In this week’s research review, we see that for people struggling with their weight, how they see their body is just as important as — if not more important than — the biology of their body.

Body image: evaluation and investment

We all went through an awkward stage as a teenagers. Heck, you may still be in an awkward stage 30 years later.

Looking in the mirror or fretting over a picture. Is that what I really look like?! The horror! If I could just lose/gain x pounds, lift this, and tuck that, THEN I would be happy. You know the drill.

Body image is how we perceive our physical appearance — good or bad — as well as how important your body perceptions are to you. Body image is separated into two parts (aka attitudinal dimensions):

1. Evaluative body image: How you think and feel you look, as well as how happy you are with your body. This is your cognitive appraisal and associated emotions (aka what you think or feel). It doesn’t necessarily mean this is reality.

2. Body image investment: How important body image is to you and how much body image affects your daily life. Being preoccupied with the way your body looks (body concern) is a hallmark of dysfunctional body image investment. Another part of body image investment is social physique anxiety, which makes you anxious in social settings and during interactions with others because you feel that others are judging your body.

So, you might not like your body much (evaluation) but not really care an awful lot (investment). This might mean you treat your body like an ugly but necessary inconvenience, like having to clean out the cat’s litter box. Gross, but what are ya gonna do, you think.

Or, you might think you look great (evaluation) and find that greatness really, really important as well (investment), which might mean that you spend a lot of time being afraid of losing that hot bod.

Of course, many of us have the worst of both worlds. We don’t like our bodies, and because we’re so invested in body image, our perceived-grotesque physiques make us want to hide under a rock.

Whether evaluation and/or investment, we tend to think of “body image” as something that happens inside our head. But could it affect our actual bodies?

What role does body image play in weight loss?

In this week’s review, I look at whether improving body image may help women lose weight over a year-long behaviour change program.

Carraça EV, Silva MN, Markland D, Vieira PN, Minderico CS, Sardinha LB, Teixeira PJ. Body image change and improved eating self-regulation in a weight management intervention in women. Int J Behav Nutr Phys Act. 2011 Jul 18;8:75.

Methods

A group of obese women went through a year-long weight loss program that focused on behaviour changes.

You may be thinking, Well aren’t all weight loss programs behaviour changes? Yes, but this one focused on self-regulation of eating (with an approach known as self-determination theory) rather than calorie counting or specific meal plans.

Our own Lean Eating program at PN focuses on eating self-regulation, which bothers some people who may be expecting a auto-pilot type of approach. What — I don’t get a list of meals? Or a meal plan to follow? You mean I have to pay attention to how my body feels and I have to make decisions!?

Now, I get that it’s often easier to let other people make decisions for you. However, the advantage of self-regulated eating is that mindful, voluntary and self-directed eating is more sustainable long-term, while fostering independence. You learn the skills you need to eat better… for life… without someone else looking over your shoulder.

Scary at first, but a lot more sustainable and useful. (Trust us. We’ve helped thousands of clients.)

Self-regulation

Several factors guide self-regulation of eating:

• confidence that you can do it (eating self-efficacy);
• consciously controlled eating that isn’t too rigid (highly flexible cognitive restraint );
• less emotional eating; less eating triggered by specific situations; and less eating because of habits (reduced dis-inhibition including emotional, situational and habitual cues); and
• less perceived hunger.

The women also increased their level of physical activity, but as with the eating, there were no specific prescriptions for what to do each day.

Body image sessions

Half the women also went to body image enhancement sessions to improve their body acceptance and satisfaction (evaluative body image) and decrease their over-preoccupation with appearance (investment in body image).

Exercises to improve body acceptance and evaluation included:

• looking at a mirror and systematically looking at body parts;
• making realistic goals and expectations for their bodies; and
• creating a realistic ideal body based on their parents’ weight history and their body type.

Exercises to improve investment in appearance included:

• understanding body image;
• finding the cause of the disorder (what situations — social and personal — triggered dysfunction?);
• keeping a diary to record negative self-talk and the feelings it causes;
• helping the women to cope with prejudice;
• helping the women let go of the belief they need to look different in order to be happy.

How do you measure body image?

You might be wondering how you measure body image and the different parts that make it up. There are a series of questionnaires and scales to indicate someone’s body image.

For evaluative body image, one of the more interesting and easy scales to use and understand is the figure rating scale (Figure 1). This provides a series of body outlines numbered 1 (very thin) to 9 (very heavy).

Participants pick the number they think fits their actual body size, and then they pick the number that represents their ideal body size. The bigger the difference (self-ideal discrepancy) the more body image issues a participant has.

Keep in mind this is perceived body size, not real body size. People may actually be their ideal body size but not think so. If you think you’re a 9 on the scale but you’re really a 1, you’ve definitely got a problem.

Body image investment is assessed using questionnaires that ask things like:

• How often do you feel fat when taking a bath?
• How often has your body shape/size kept you from concentrating?
• How nervous do you feel about your body in social settings?

Figure 1: Figure Rating Scale. From Bhuiyan et al, 2003.

Results

Improved body image

The body image sessions worked. The women in these sessions improved both evaluative body image and body image investment.

Improved eating self-regulation & weight loss

Improving body image also improved eating self-regulation. With better eating, there was better weight loss.

The body image group lost 7.3% of their body weight, while the control group lost only 1.7% of their body weight.

It makes sense that better eating means more weight loss, but seems odd that a better body image would help weight loss. Wouldn’t you think that people should lose weight first… and then feel better about their bodies?

Not in this case. The group that got care, counselling, and compassion kicked ass. Goes against the drill sergeant/tough love approach, doesn’t it?

Using a mathematical model (partial least squares) the researchers found that changes in body image investment was a little more important for weight loss than body image evaluation. In other words, to lose weight, it’s more important to let go of rigid investment in body size and shape than it is to always feel great about yourself.

(After all, remember our hypothetical people who feel good about their body, but are afraid of losing it? They’re much more likely to rigidly control their eating and exercise, which sets them up for problems like diet rebounds, exercise compulsions, and binge eating later on. Plus, if you’re not as invested in your body image, you realize that small things like day-to-day weight fluctuations aren’t that big a deal.)

Conclusion

You’d think people would be motivated to change if they were unhappy with their body. In fact, the opposite is true: Greater body image dissatisfaction actually hinders weight loss.

You may need a certain amount of dissatisfaction with your current body if you want to change it, but more isn’t better. Pointing out that someone is overweight or obese, or beating up on yourself, doesn’t make you more motivated. Nor does it help you get leaner.

We know this to be true. In Lean Eating, we use an “awesomeness-based coaching” approach. We don’t spend time pointing out your “flaws” or “problem areas” (imaginary or otherwise). We find what’s already awesome about you, right now, no matter what your body looks like… and help you do and feel more of that.

(And just a warning: We have a Five-Pushup Rule in Lean Eating: Self-criticism gets you five pushups. We know that negative self-talk doesn’t do you any good. So we pushup that nasty stuff right outta you.)

This study shows that improving body image helps with weight loss. And it seems that spending less time worrying about how your body looks and how other people may scrutinize your body is a bigger part of the puzzle than how unhappy you are about your body.

Want to lose weight?

• Stop obsessing about your body. If possible, try to get “outside yourself” — into a bigger world full of activities, experiences, social causes, and other things more interesting than whether you can see your abs.
• Pursue self-acceptance, self-care and self-compassion… not self-criticism.
• Pay more attention to what you eat — eat slowly and mindfully.
• Move your body more.

Simple, but not necessarily easy.

Bottom line

Whether you’re coaching a client or are interesting in losing weight yourself, improving body image can help you lose weight.

As counter-intuitive as it sounds, accepting your body as it is and spending less time thinking about your body can improve your weight loss. You still have to eat a little less and move around a little more… but at the very least, you’ll also like yourself at the end of the day.

References

Bhuiyan AR, Gustat J, Srinivasan SR, Berenson GS. Differences in body shape representations among young adults from a biracial (Black-White), semirural community: the Bogalusa Heart Study. Am J Epidemiol. 2003 Oct 15;158(8):792-7.

Summary: Microwave ovens usually don’t destroy nutrients in food. If using a microwave helps you eat more nutritious foods and less junk food, then keep it. But there are potential harmful effects from too many electromagnetic frequencies, and doing without a microwave is one way to limit exposure.

Unprocessed foods.
Whole foods.
Local foods.
Microwaved foods.

Which one of those is not like the other?

When we use a microwave, what purpose does it serve? Are we using it to reheat our “unprocessed food” leftovers from a recipe we made after shopping at the farmers market? Or are we using the microwave to get that Pop-Tart juuuusssst right?

Up to 93% of American homes have and/or use microwaves, so obviously there is something appealing about them. But do any of us really know the long-term health implications of repeated microwave use? And does microwaving food affect the nutrients it contains?

How microwave ovens came to be

Percy Spencer was building radars in the 1940s and discovered that microwaves from radars melted a candy bar in his pocket. Fast forward seven years and we had the first “radarange” in 1947 at a Boston restaurant. It weighed about 700 pounds and cost nearly $5000.

People weren’t excited about cooking food with “radar,” so the name was changed to “microwave oven”. The first popular microwave for home use was introduced in 1967. As more women were entering the workforce, anything that saved time in the kitchen was welcome. An advertising campaign coincided with housewives using microwave ovens followed by young female sales personnel travelling around North America proclaiming their benefits.

The original microwave oven patent

 

How microwaves work

Inside-out cooking

Conventional cooking transmits heat to the outside food by convection (baking), radiation (broiling), or conduction (frying). This heat then makes its way to the inside of the food. This can take a while, as anyone who’s frantically tried to roast a semi-defrosted turkey can attest.

Microwaves, by comparison, start on the inside of the food.

Microwaves are a form of electromagnetic energy (radiation), like radio waves or light waves. When absorption of microwave energy interacts with molecules in food, heat is generated and the food is cooked (think of rubbing your hands together really fast).

The source of radiation in a microwave oven is the magnetron tube, which converts an electric current to electromagnetic radiation. Microwaves can travel through glass, but metals reflect them. This is why microwave doors have a metal screen.

Energy use

Because they heat the food from the inside out (rather than outside-in), microwave ovens have a better cooking efficiency (the % of energy that heats food during the cooking cycle) than electric or gas convection ovens.

Oven type	Efficiency
Microwave	57%
Electric convection oven	17%
Gas convection oven	9%

Microwaves also use less electrical power than conventional type electric ovens.

Oven type	Watts
Microwave	750-1100
Toaster oven	1200-1700
Electric oven	3000-8000

 

The effects of microwaves on food

Nutrients

Although you may have heard that microwaves kill nutrition, that doesn’t seem to be true.

Microwave ovens usually don’t destroy nutrients in food. And in some cases, preparing food in a microwave might actually promote nutrient retention.

Nutrients are leached from food during any form of cooking, especially when the food is cooked for a long period of time with high amounts of water. So, for example, boiling carrots might strip nutrients much  more drastically than microwaving them, because the carrots’ nutrients might get washed away with the boiling water.

However, since we haven’t discovered all the compounds that make up food, we’ll likely never know all of the outcomes that microwaving has on nutrients.

Protein

Protein quality seems to be fine with microwave heating. Some data indicates that amino acids and vitamin B12 may be converted to inactive forms.

But on the flip side, availability of some amino acids might be improved, since no surface browning occurs. And microwave heating might lead to destruction of trypsin inhibitors in beans. Bonus!

Breast milk

Microwaving breast milk breaks down the antibodies and vitamin B12 (this also occurs with conventional boiling, but it takes about 25 minutes or more).

By the way, speaking of organic fluids, heating blood for transfusions in microwave ovens can result in hemolysis (but hasn’t been shown to damage DNA).

Food safety and carcinogens

Microwave cooking forms fewer nitrosamines and AGEs on meats than conventional cooking methods. For more on AGEs, see here.

Taste

Taste preferences are individualized. Still, restaurants usually don’t advertise “microwaved green beans” on the menu.

Microwave cooking doesn’t result in surface drying or browning reactions, so this alters the flavour and appearance of foods (especially meats and breads).

Some microwavable foods will come with a gray paperboard for heating. This paperboard contains an extremely thin metal coating of resistant polymer film which absorbs microwave energy, converting it into heat for browning. Certain additives can also be put on the surface of food to achieve this effect. Gosh, now I’m having flashbacks of microwavable pizzas in junior high.

The health effects of microwaves

Ahhh, the 1980s. Micro Machines, slap bracelets, American Gladiators and Hans Hertel.

Wait… who’s Hans Hertel? Well, Hertel and Bernard Blanc, two Swiss scientists, did some experiments with microwave cooking. They found subjects to have lower hemogloblin and higher white blood cells and blood cholesterol after eating microwaved food. However, this data was never published in a peer reviewed journal.

The Swiss appliance industry wasn’t excited about these results and took the scientists to court. Hertel and Blanc were convicted of interfering with commerce, but the ruling was later reversed (see reference section for more info).

Electromagnetic radiation

When microwave ovens were first available to the public, tests showed that they leaked excessive electromagnetic radiation. This type of radiation is non-ionizing, which means that it isn’t the type of “radiation” you’d associate with Homer Simpson and Chernobyl — it’s in the form of waves.

Early microwave ovens worked by sending wavelengths similar to many of today’s phones (915 mHz). The main difference between phones and ovens is that the power needed to operate a microwave oven – about 1000 watts – is much greater than that needed for a cell phone. Cell phones operate with less power but at the same wavelength as microwave ovens.

In the United States, the FDA allows some radiation leakage. In the 1970s, Consumer Reports declared that microwave ovens were “not recommended,” and the Soviet Union actually banned microwaves for a short time (no countries ban them today).

Exposure to radiation is highest within two inches of the microwave. Yet, the amount of electromagnetic radiation we are exposed to from microwave cooking is less than cell phones (measured cumulatively).

When our body absorbs microwave radiation, we take on the energy as heat. Some tissues are sensitive to this. Strong fields of electromagnetic radiation may raise cancer risk, affect the nervous system, and promote other problems (such as Alzheimer’s disease). There is a correlation between microwave cooking and oral cancers/salivary gland tumors, but this might be due to the production of heterocyclic amines in food. Some data indicate that cooks may have higher risks of cancer due to microwave radiation exposure, but the body of evidence is still not clear on this.

If our only exposure to electromagnetic frequencies is via microwave cooking, it probably wouldn’t be a big deal. But add up total exposure and it becomes a concern.

We absorb EM radiation from power lines, cell phones, airplane flights, computers, fridges, and so forth. There is growing evidence that effects of microwave radiation add up over time.

However, the radiation from microwave ovens alone is so low that it shouldn’t damage DNA. And there is no legit data indicating a direct negative impact of microwave ovens on human health.

“We don’t have a solid position on the possible health risks from exposure to microwaves due to inconclusive research. The real question remains whether there could be cumulative effects.”
–Norbert Hankin of the Environmental Protection Agency (EPA)’s Center for Science and Risk Assessment

Plastics

Many plastics, when heated, release toxic and endocrine (hormone) disrupting compounds into the food. So don’t microwave food in plastic, especially in plastic containers not labeled “microwave safe”. And styrofoam… well, just don’t go there.

The term “microwave safe” has mixed support – some say it’s legit, some say it’s not regulated. And by the way, exposing plastic to any type of heat (in the oven, microwave, campfire, etc.) has the same negative outcome. Microwaving just speeds up the process. And most of us aren’t likely to try to use Tupperware as a frying pan. (Well, at least not after the… unfortunate… incident.)

Dyes haven’t been approved for microwave use, so don’t assume you’re problem-free if you’re using coloured paper towels or paper containers.

Bacteria

Food heated in a microwave oven can have uneven temperature distribution. The food (or part of the food) with the highest water content heats up the quickest. This is why many oven models include a rotating tray: it distributes the waves more evenly.

Uneven food temperatures may allow microorganisms — including Salmonella, Listeria, Clostridia and Campylobacter — to survive.

So when you’re cooking or reheating, make sure the food is thoroughly heated, and occasionally turn or stir food if possible.

The great exploding cup of tea

Heating up liquids in the microwave can prevent bubbles from forming. The water can become overheated past the boiling point. When the liquid is agitated (say by stirring it or dropping a bag of tea in it), it can erupt. So watch out and don’t set your tea to “volcanic”.

Summary and recommendations

Microwave ovens usually don’t destroy nutrients in food. If using a microwave helps you eat more nutritious foods and less junk food, then keep it. But there are potential harmful effects from too many electromagnetic frequencies, and doing without a microwave is one way to limit exposure.

If you use a microwave:

• Don’t heat food in plastic.
• Make sure food reaches 160 degrees F in all areas (you have a food thermometer, don’t you?).
• Cover food to help ensure uniform cooking.
• Allow the food to sit a few minutes after microwaving.
• Microwave food only as long as necessary, with little to no cooking water.
• Keep the microwave out of high traffic areas.

If you don’t use a microwave:

• You can eat leftovers cold. If you don’t have to reheat – don’t. Each time we reheat, no matter the method, we are going to lose nutrients.
• Try the stove, including steaming or stir-frying.
• Use the oven, including baking and broiling.
• Consider a toaster oven, which uses less energy than a conventional oven. (Heck, consider a solar cooker. Just sayin’.)
• Heat water in an electric tea kettle.

Resources

Video – History of the microwave oven
What happens to food in the microwave and in slow motion
FDA – Microwave Oven Radiation

References

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The Effect of Income on Appliances in U.S. Households. March 26, 2009.

Microwave Oven – Wikipedia.

O’Connor A. Really? October 17, 2006.

Howard BC. Seven surprising facts and myths about microwave ovens. July 14, 2009. The Daily Green.

Song L & Thornalley PJ. Effect of storage, processing and cooking on glucosinolate content of Brassica vegetables. Food Chem Toxicol 2007;45:216-224.

Cross GA & Fung DY. The effect of microwaves on nutrient value of foods. Crit Rev Food Sci Nutr 1982;16:355-381.

Heimbuch J. Microwave or toaster oven, which is the greener kitchen gadget? April 22, 2009. Tree Hugger.

Microwave ovens and their hazards. Canadian Centre for Occupational Health and Safety. November 2, 2004.

Sugarman E. Warning: The electricity around you may be hazardous to your health. Simon & Schuster. 1992.

David D. Disconnected. Penguin Group USA Inc. 2010.

Levitt BB. Electromagnetic fields. A Harvest Original. 1995.

Allen KJ. Is your kitchen microwave safe? The Environmental Magazine. August 31, 2004.

Netherlands Institute of Human Rights. Hertel v. Switzerland. 1998. No. 87.

Taghavi N & Yazdi I. Type of food and risk of oral cancer. Arch Iranian Med 2007;10:227-232.

Steneck NH. The microwave debate. The Massachusetts Institute of Technology. 1984.

Lopez-Berenguer C, et al. Effects of microwave cooking conditions on bioactive compounds present in broccoli inflorescences. J Agric Food Chem 2007;55:10001-10007.

Schmidt-Pokrzywniak A, et al. A case-control study: occupational cooking and the risk of uveal melanoma. BMC Ophthalmology 2010;10:26.

Ohlsson T & Bengtsson N. Microwave technology and foods. Advances in food and nutrition research 2001;43:65-140.

Cross GA, et al. The effect of microwaves on nutrient value of foods. CRC Critical Reviews in Food Science and Nutrition 1982;16:355-381.

Driskell JA, et al. Effects of induction, conventional, and microwave cooking on sensory qualities and carotenoid retention in selected vegetables. Poster. J Am Diet Assoc 2006;Suppl 2:106:A-42.

Schardt D. Microwave myths. Nutrition Action Healthletter. 2005:10-12.

Kadey M. Inside the microwave. Experience Life. Jan-Feb 2012.