Nutrition & Physical Activity

Share this

Eating at night = weight gain: Myth or fact?

Dear Reader,

You and your friends have picked up on a popular debate. One aspect of weight management that is vital to understand is that we gain and lose weight over periods of time — weeks, months, years — not hour by hour. This happens as we take in more calories than we expend. Another important fact of metabolism is that our bodies do not stop working, even when we are sleeping! Hearts are beating, blood is circulating, lungs are functioning, brains are even working. This all takes energy — meaning we are still burning calories.

There is no magic time after which the body stores fat. For instance, if you eat the same exact meal at 6 pm or at 8 pm, is one more caloric than the other? No, each meal has the same number of calories. What really matters is the total amount of food and drink you have over the course of a week, or a month or longer, and how much energy you expend during that timeframe. Excess calories will be stored as fat over time, regardless of whether they are taken in during the day or night.

When it comes to eating late at night and the potential for weight gain, there are several considerations:

  • Portion sizes — waiting to eat could lead to consuming larger portion sizes.
  • Quality of food — after a long day of work or school, a few slices of pizza or a fast burger may seem easier than steamed vegetables and broiled fish.
  • "Mindless snacking" — evenings spent studying, going out, or watching TV may lead to excess calories from fast, sugary, on-the-go options.
  • Health concerns — consistent periods of going without food followed by a large meal can negatively impact the interaction between blood sugar and insulin and make you more vulnerable to Type 2 diabetes.

So, to settle the debate, you are correct that late-night calories won't change your metabolism or magically count more than calories eaten during the day. However, limiting late-night meals and snacks may be an effective weight management strategy for some because it helps them to control their overall calorie intake. Some people find that if they set a time that they can't eat past, it helps minimize or eliminate the possibility of munching on a lot of high calorie foods. Another useful tip may to be to eat four or five smaller meals and snacks spread evenly throughout the day so you don't become overly hungry at any point. Following these tips can keep your energy levels consistent for work and play and can provide some long-term benefits to help you reduce your chances for diabetes or other health issues. 

Bon appétit! 


June 29, 2007

Dear Alice,

Though your metabolism IS constantly at work, it does slow down later in the day, especially if you are just dieting and not exercising. When you exercise your heart rate and...

Dear Alice,

Though your metabolism IS constantly at work, it does slow down later in the day, especially if you are just dieting and not exercising. When you exercise your heart rate and metabolism both increase. In addition it is better to eat more meals and take in the same amount of calories because in doing so you keep your metabolism working. On the other hand if you eat less or worse starve yourself for several hours your metabolism slows down and potentially puts your body into a "starvation mode" where more insulin is released causing the body to store more fat. This is the most simple answer to this question.

Foods plentiful in potassium

Dear Reader,

Don't monkey around and limit yourself to bananas! Although bananas are known to be rich in potassium (one medium banana has about 422 milligrams), there are plenty of fresh, whole foods available that can supply you with an abundance of the essential mineral. Some of the best sources include:



Potassium (in milligrams)

Potato, baked with skin

1 small


Prune juice

1 cup


Tomato paste

¼ cup


 White beans, canned

½ cup


Plain yogurt, low- or non-fat

½ cup


Orange juice

1 cup


 Cod, cooked

 3 oz.


 Spinach, cooked

½ cup


Skim milk

1 cup


Apricots, dried

¼ cup



½ cup


Table adapted from the United States Department of Agriculture’s Dietary Guidelines for Americans.

The Adequate Intake (AI) for adults is currently 4,700 milligrams per day. AI refers to an amount of a nutrient that is suitable for most people, but also means that some people may be fine with getting slightly less than the AI amount.  While this may seem like a lot, eating a well-balanced diet rich in fruits, vegetables, beans, and legumes will likely satisfy your potassium AI. Potassium plays an integral part in the body, maintaining the balance of fluids and electrolytes inside your body's cells. It also has a hand in normalizing blood pressure, muscle contraction, and transmission of nerve impulses.

Potassium levels can drop while sweating, dieting, using diuretics or laxatives, vomiting, or during bouts of diarrhea. When your potassium levels drop severely, your body can no longer detect the need for water. Severe losses can result in heart arrhythmias, confusion, nerve damage, and paralysis, while generally low potassium intake can raise blood pressure, worsen glucose intolerance, increase metabolic acidity, accelerate calcium bone loss, and increase the likelihood of developing kidney stones. Muscle weakness, cramping, and/or nausea may indicate a potassium deficiency.

Eating a well-balanced diet rich in fresh, whole foods is your best source of potassium. Though most Americans don’t get enough potassium, some folks, such as those with kidney disease and those who take certain medications may need to health care provider about a lower potassium intake.  Potassium supplements are not recommended unless under the direction of a health care provider because they can be dangerous for a healthy adult.


A bowl of oatmeal a day keeps the cholesterol at bay?

Dear Haulin' Oats,

According to the 1990 Nutrition Labeling and Education Act, the U.S. Food and Drug Administration (FDA) may authorize a health claim only if there is significant scientific agreement that it is true — meaning that the claim must be accurate and not misleading to consumers. In 1997, the FDA allowed whole oat food manufacturers to make the health claim that their products reduce the risk of heart disease. Scientifically, the basis for this assertion is that the dietary fiber found in oats has been shown to help lower cholesterol, one of the risk factors for cardiovascular disease.

Oats contain beta-glucan, a water-soluble fiber thought to decrease LDL (low density lipoprotein, the harmful cholesterol) and total cholesterol. Since soluble fiber has a high water-holding capacity, it becomes gooey when dissolved in water. This feature allows soluble fiber to travel slowly through the digestive tract and attach to bile acids in the intestine, and then carry the acids out of the body as waste. Since bile acids are made from cholesterol, soluble fiber helps with the absorption of less dietary cholesterol.

In order to put the health claim on the food label, the oat item must be whole oat and provide at least 0.75 grams of soluble fiber per serving. In addition, the health claim must also include the words, "Diets low in saturated fat and cholesterol" rather than “Diets high in oats;” otherwise, consumers may think that eating oats is all they need to do to lower their risk of heart disease.

So, how much oats does a person really need to get the health benefits? Research has shown that two servings of oats daily can reduce cholesterol two to three percent beyond what is achieved with a low-fat diet alone. Other sources of soluble fiber may help instead of, or in addition to, the oats. Some examples of dietary soluble fiber include:

Food Serving Size Soluble fiber (grams)
Kidney beans (cooked) ½ cup 2.0
Pinto beans (cooked) ½ cup 2.0
Brussels sprouts (cooked) ½ cup 2.0
Oat bran (dry) 1/3 cup 2.0
Orange 1 medium 1.8
Oatmeal (dry) 1/3 cup 1.3
Apple 1 medium 1.2
Broccoli (cooked) ½ cup 1.1
Grapefruit ½ medium 1.1
Spinach (cooked) ½ cup 0.5
Brown rice (cooked) ½ cup 0.4
Whole wheat bread 1 slice 0.4
Grapes 1 cup 0.3

To reduce the risk for heart disease further, it is necessary to keep weight, cholesterol, and blood pressure at healthy levels, don't smoke, and exercise regularly. Also it is beneficial to munch on plenty of fruits, veggies, and whole grains. For more information on healthy eating, you can check out the United States Department of Agriculture (USDA) MyPlate website.

Lastly, while oat cereals are part of a healthy eating plan, if you can't stand them, don't force feed yourself. You can incorporate many other strategies and dietary sources of soluble fiber into your lifestyle to achieve better heart health. To life!


Spinning out of control?

Dear Always spinning at 85%,

It's good to hear that you, as the instructor, are attuned to the well-being and safety of your class participants. Finding creative ways to address attitudes and perceptions surrounding exercise can be an ongoing challenge.

The intensity at which an individual chooses to exercise depends on several things, such as health status, current fitness level, and fitness goals. Every body is different, and sometimes, especially in group exercise situations, competitiveness and/or insecurity triggers the group to conform to a norm (in this case, high intensity spinning). Often, though, a lack of accurate information interferes with people's development of useful attitudes and informed opinions about how they themselves need to exercise. You mention that the main goal for your classes is weight control. Exercising regularly at a high intensity level is not necessarily the best way to lose/control body weight.

So first, gather the data you need to teach your clients the facts. In Exercising beyond my maximum heart rate — Is this safe?, the answer explains how the conventional heart rate equation may not truly suit everyone. A more accurate way to determine one's training zone takes his or her resting heart rate (RHR) into account. Although it still is based on the estimated maximal heart rate formula, (220 - age in years), it serves as a better reflection of one's aerobic capacity.

(By the way, the most accurate calculation would directly measure one's functional capacity, or the amount of oxygen consumed during exercise.) For most people, the following calculation, known as the Karvonen formula, is fine. It is:

[(220 - age in years) - Resting Heart Rate] x Exercise Intensity + Resting Heart Rate

So, a forty-year-old with a RHR of 47 beats per minute could work within the 65 - 85 percent of maximum heart rate range of 133 - 160 beats per minute:

220 - 40 = 180
180 - 47 = 133
133 x 65 % = 86
86 + 47 = 133 beats per minute (low end)
220 - 40 = 180
180 - 47 = 133
133 x 85 % = 113
113 + 47 = 160 beats per minute (high end)

Next, perhaps you can learn more about why your clients believe that they need such intensity to "feel like they are getting a workout." What do you suppose is fueling this attitude? Ask some of your clients, something like, "I notice that you ride really hard when you come to class. Do you spin at that intensity all the time? And if so, what is that about? What is it that you want to happen?" Or, strike up a conversation about specific fitness goals.

Once you have the information you need and a better sense of what is motivating your class participants, you'll be in a better position to intervene. What may also help is to start an ongoing dialogue about individual fitness goals related to spinning. For example, you can explain that an "all out" exhaustive workout isn't appropriate for everyone and/or every day. You can encourage your clients to focus on higher intensity activity some days, while other days concentrate on workouts of longer duration at a lower intensity level. You can also explain that exercisers can engage in "active rest," meaning they don't necessarily have to become couch potatoes on their days off. They can go for a walk, practice yoga, jog, swim, bike, or dance at a much more leisurely pace. To help improve overall fitness, encourage cross-training — running, rowing, swimming. And you can explain the benefits of each of these kinds of movement.

Employing different techniques keeps your classes exciting for your class participants, and for yourself, as well. You said that you already vary the classes' intensity. Many instructors incorporate interval training, which changes the intensity during a class. Participants are challenged by the variety. Another option is to offer a longer class at a slightly lower intensity, for a change of pace.

You have the tools and information to help class participants reach their goals, and at least some of these ideas will make a difference, helping you reach your goal of getting your clients to learn more about what "works"!


What's up with iodized salt - Is it better for you than regular salt?

Dear Wondering,

Great question! Iodine is a mineral that is added to table salt and found in a variety of foods. It is important for good health and, fortunately, our bodies require it in relatively small quantities. Iodine is part of a hormone, thyroxin, which is responsible for maintaining a person's metabolic rate.

Iodine is found in the sea and in soil that has previously been under the sea. Salt water seafood (e.g., sea trout, lobster, haddock, shrimp, and shark), sea vegetables (such as seaweed, including kelp, hijiki, arame, nori, and laver), vegetables grown in soil containing iodine (found on any land that was previously under the sea), and animals grazing on plants growing in iodine rich soil all are good sources. This mineral also enters the food supply through the use of certain disinfectants called iodophors. These are primarily used in the dairy industry, so milk and cheese, for example, contain a good amount of iodine. In addition, some red dyes contain iodine, as do some dough conditioners (look for an iodized conditioner listed in the ingredient section on the bread package). These sources add considerable amounts of iodine to one's diet.

As you can see, there are many ways to obtain iodine other than through table salt. That was not always the case. Many years ago, when iodine wasn't as plentiful in the food supply and people relied on iodine mainly from the sea, many people in the Great Plains states and Willamette valley in Oregon in the United States, which are situated far from salty waters, had iodine deficiency. Salt fortification was initiated in the U.S. to eliminate goiter, a disease of the thyroid gland resulting from iodine deficiency.

Now, food is manufactured and shipped all over the U.S. and the world. Food containing iodine is available everywhere. It is much less likely for people, even those living far from the ocean, to have goiter nowadays. However, salt is still iodized because iodine levels can vary greatly in foods (as levels of iodine in the soil are quite variable), and fortification offers a margin of safety. Today, goiter is more prevalent in developing countries than in the U.S., because they don't have access to as many foods, such as plant foods, that were grown in iodine-rich soil, they aren't eating seafood, and the populations of some developing countries are malnourished in general.

So, in answer to your question, it sounds as though you and members of your household are probably not taking in much salt if that package lasts forever. If you are eating plenty of seafoods — saltwater fish and/or sea vegetables — you don't need to return your salt. If you are eating a varied diet, you are probably taking in sufficient iodine. However, if you avoid most of the foods mentioned here, you may want to reconsider getting iodized salt, just to be on the safe side.

The Recommended Dietary Allowance (RDA) for iodine is 150 micrograms (µg) a day for adults. Women who are pregnant should consume about 200-300 micrograms because iodine is important for fetal and infant brain development. Iodine content varies widely in foods, as shown in the following examples:

Food source Iodine content (in µg)
Salt, iodized, 1 tsp. 400
Bread, made with iodized conditioner, 1 slice 142
Haddock, 3 oz. 104 - 145
Cottage cheese, ½ cup 26 - 71
Shrimp, 3 oz. 21 - 37
Cheddar cheese, 1 oz. 5 - 23

As a side note — lots of processed foods contain high levels of sodium. This sodium is not iodized, so don't count on meeting your iodine needs through chips and other junk food!


Eliminate all body and dietary fat — healthy?

Dear Anonymous,

In a word, no! Fat — both on our bodies and in our diet — gets an undeserved bad rap and is actually essential for our survival. Body fat is found in places you may not even think about when you're considering its role in our health. It's part of:

  • Every cell membrane
  • Some hormones and prostaglandins (hormone-like substances) which regulate many body functions
  • Nerve sheaths (nerve coverings)

Body fat is categorized as either essential or storage fat; both types play a vital role in our functioning. Essential fat is found in bone marrow and lipid rich tissues throughout the body. Storage fat is located around internal organs and under the skin (subcutaneous). These two types of body fat play important roles in keeping our bodies healthy. For example:

  • A layer of fat surrounds each organ (such as your heart, liver, kidneys, etc.), protecting and cushioning it against impact during sports or accidents,
  • Fat helps maintain normal body temperature.
  • Fat provides us with a supply of stored energy, which can sustain us if food is not available.

Dietary fat is the fat found in a variety of foods and is a concentrated source of energy for the body. It is dangerous to eliminate all fat from your diet. Certain fats, essential fatty acids, can only be obtained from foods. These are incorporated into regulators of specific body processes such as blood pressure and even help us maintain healthy skin. Dietary fats are also required to absorb vitamins A, D, E, and K. These nutrients are vital to our vision, bone formation and maintenance, blood protection and clotting, nerve development, and can act as a defense against oxidation. In addition to their health benefits, fats provide joy in eating. They carry flavors and aromas, and provide foods with pleasurable textures. Fats also fill us and help satisfy our appetite.

When it comes to fat, too much or too little on our bodies and in our diets is not recommended. The related Q&As can shed some more light on the facts about fat.


Unscrambling conflicting info about eggs

Dear Not yet an Eggspert (but hopefully soon-to-be one),

You're right — eggs are a great form of protein, among other nutrients. The reason you hear different recommendations is because they vary depending on a person's health. Each person responds to dietary cholesterol differently, meaning that eggs may have more of an effect raising one person's blood cholesterol than another's. Unfortunately, we can't tell who will be affected in advance. If you're a healthy person, the American Heart Association says you should consume 300 mg or less of dietary cholesterol per day. If you have any of the following risk factors, 200 mg or less is recommended:

  • Family history of heart disease
  • Total cholesterol over 240 mg/dl
  • High blood pressure
  • Diabetes
  • You smoke

One whole egg contains between 213 - 220 mg of cholesterol. The fat, cholesterol, and most of the vitamins and minerals are found in the yolk. By the way, the saturated fat content of an egg is less than 2 grams, which is low. If you are in good health and know that your total blood cholesterol is below 200 mg, it is probably okay to have one whole egg a day if you limit other sources of cholesterol. The American Heart Association recommends 3 - 4 egg yolks per week for healthy individuals, probably because they expect that people will eat other foods that have cholesterol — these include all other animal-based products, some containing more cholesterol than others. To give you an idea:

  Food Item

Dietary Cholesterol (mg)
  whole milk (1 cup)   35
  skim milk (1 cup)   4
  cheese (1 oz.)   20 - 30
  butter (1 T.)   35
  beef (3.5 oz.)   70 - 100
  chicken (3.5 oz.)   75 - 90
  shrimp (3.5 oz.)   215
  cod (3.5 oz.)   65

If you're eating eggs and other high cholesterol foods often, it would be wise to have your blood cholesterol levels checked regularly to be sure that they don't suddenly rise.

Whipping up omelets using one whole egg and two or more egg whites is a good idea. This will give you a nice, fluffy dish with flavor, too. If you're looking for other low-cost nutritious foods, try preparing simple bean dishes. Since the fiber in beans helps to lower blood cholesterol levels, this could be a healthy alternative for egg-less times.

Have an egg-cellent day,


Boosting my booty


Your desire for a bulbous backside may butt up against your genes, not to mention gravity and aging. But don't despair, despite your flat-assed family, some exercises and fashion choices can lift and tighten your tail — which, by the way, is comprised mostly of fat and gluteal muscle.

The running you mention is a great way to enhance many aspects of your fitness. Have you considered adding in some other forms of activity to supplement your weekly miles? A combination of weight training and some new forms of cardio may provide the boost you seek. Have you considered a consultation with a personal trainer to help guide you with your goal? If you are a Columbia student, you can meet with a certified trainer from Dodge Fitness Center. Also, consider checking out CU Move, an initiative that offers the University community opportunities to learn about and engage in physical activities that support healthy living.

In addition to a consultation with a trainer, an array of online videos, tips, and research may provide some perspective. A quick internet search for "glute exercises" provides a range of links. It's best to consult with a reputable source to determine the best type of activity. The American Council on Exercise reports on research in many areas of health and fitness. Visit their website for the latest resources, including findings on how to build those glutes.

Some consistent recommendations across sources include:

  • Lunges
  • Step-ups
  • Hip extensions
  • Squats (various types)
  • Cross country skiing (in the woods or at the gym)
  • Stair climbing
  • Blading or skating

In addition to the fitness side of building a backside, have you considered some fashionable ways to bring out your caboose? Pants, underwear, and bathing suits may change the definition of your derriere by elevating and pulling it, or simply making it appear to be shaped in a way that only you know it's not. If you don't mind the filling and feeling, padded underwear (similar to what padded, push-up bras may do for breasts) may create the illusion of a fully formed butt. A lot of clothing styles may also do the trick, and not all of them are expensive. Grab a friend for some fanny feedback and spend a day trying on different pants, jeans, and shorts. With a little trial and error, you're sure to find a style that's flattering and gives you the boost you desire.

Finally, know that many people have a particular body part they perceive to be different, abnormal, too big, or too small. Indeed, the best workout may be your exploration of how to become more comfortable with your backside.


Health benefits of fish oils

Dear Curious,

Somthing's fishy about your lab results. The improvement in your cholesterol levels may be due to the foods you replaced with the fish, rather than the fish in and of itself. The fats found in some varieties of fish, omega-3 fatty acids, reduce triglyceride levels in the blood, but generally do not affect cholesterol levels.

However, you're still doing yourself a favor by feasting on fish. Eating fish offers many major health advantages. The primary benefit found from including fish oils in your diet is the lowered risk for sudden cardiac death. This means that fish eaters decrease their chance of dying suddenly from a heart attack (keep in mind that there are different types of heart attacks).

Two mechanisms explain how eating fish reduces the chance of heart attack. First, it seems that fish oil fatty acids reduce blood clotting by decreasing the stickiness of blood platelets. Second, omega-3 oils may play a role in stabilizing heart rhythms. It could be that the electrical impulses that go awry during some heart attacks are preserved in fish eaters. These protective qualities may work together, resulting in the reduced risk of sudden cardiac death that has been observed among fish consumers. Other possible health benefits of omega-3 fatty acids are their potential to help lower blood pressure and protect against some forms of stroke.

Remember, it is possible to have too much of a good thing. There are certain risks associated with eating too much fish. The main risk has to do with the toxicity of environmental contaminants, primarily mercury, which ends up in fish due to environmental pollution. Because of this, women who are pregnant or breastfeeding are often advised to avoid fish. In addition, there are various recommendations for eating fish to avoid consuming dangerous levels of mercury, as its toxicity can damage the brain, kidneys, and lungs. Mercury levels may be especially high in shark, swordfish, king mackerel, and tilefish.

But in moderate amount, fish can be beneficial, especially for people eating a western diet that is often low in omega 3s. Good sources of omega 3 include:

  • Shrimp
  • Salmon
  • Mackerel (watch out for the higher mercury levels in king mackerel)
  • Rainbow and lake trout
  • Sardines
  • Halibut
  • Pollock
  • Oysters
  • Catfish
  • Albacore, blue fin, and yellow fin tuna (including the canned type)
  • Striped sea bass
  • Turbot
  • Swordfish (watch out for higher mercury levels)

Fish oil supplements, on the other hand, contain almost no toxic contaminants and thus are safe. However, they can cause gastric symptoms, so it is best to take them with food. People with low blood pressure or who are taking medication for low blood pressure should also be careful about eating too much fish, since the fish oil could lower blood pressure even more. In very high amounts, fish oils can have some anti-coagulant effects, causing nosebleeds in some people.

Eating these jewels of the sea even once or twice a week may lead to heart healthy benefits. Obviously an all-around healthy diet will provide even more protection from heart disease, and other maladies, too.


Time-release dietary supplements

Dear Reader,

It's easy to become confused with the whole array of dietary supplements on the shelves nowadays. One form may claim superiority in advertisements, but how are you to know for sure which ones are right for you?

First of all, vitamins and minerals are needed in our bodies in relatively small amounts. Vitamins may be present in our blood, organs, or other tissues. Although each micronutrient (scientific term for vitamins and minerals) has a specific function, here's a brief overview by category:

  • Water-soluble vitamins (all the B vitamins and vitamin C) and many minerals act as co-enzymes, meaning they aid in chemical reactions in the body. Excessive amounts don't make reactions occur faster or more efficiently than adequate or recommended amounts. Plus, too much of one mineral may actually inhibit the absorption and effectiveness of another.
  • Fat-soluble vitamins (vitamins A, D, E, and K) are involved in specific roles of maintenance and repair of body cells and tissues. Unlike water-soluble vitamins, extra amounts of fat-soluble vitamins are not excreted, so over-saturation of these may lead to toxicity.
  • Minerals have a variety of functions, ranging from water and acid-base balance, to bone structure and co-enzyme activity, as mentioned before.

As long as you consume a sufficient vitamins and minerals, a constant influx is not necessary, and may also be harmful. For example, time-release niacin is not recommended because it can cause liver damage. Time-release iron supplements are ineffective because the point of release in the intestinal tract does not absorb this mineral efficiently. Some time-release supplements contain coatings that prevent the absorption of fat-soluble vitamins. As you can see, time-release nutritionals are certainly not worth the extra money manufacturers often charge for them. Besides, Mother Nature has already provided us with a way to time-release our nutrients... by getting them from a variety of foods, eaten at various times throughout the day.

To get to your last question, you are among quite a number of men and women who have expressed concern over whether their multi-vitamin "works" or "doesn't work"; that is not really the point of these supplements. Their purpose is to help certain people fill in nutritional gaps when they are unable to eat enough food or obtain adequate vitamins and minerals from their diet. Multi-vitamins also might be recommended for some vegetarians, dieters, and others who have food allergies, intolerances, or other problems associated with eating particular foods. A supplement may benefit the elderly, too, because sometimes older people can't absorb nutrients as well as they did in their youth. Remember, the meaning of a dietary supplement is to add to a diet, not to take the place of food!


Syndicate content