Nutrition Science 101

It may surprise many of you to know that I don’t actually think you need more nutrition information. I am a dietitian, after all, and it’s my job to inform and provide nutrition education. So here’s the thing: you don’t need more nutrition info, but you need better, more factually and less biased information so that you can be an informed consumer.  What most Americans don’t realize is that they are being strung along on a wild journey, jumping from one food fad to another. Everywhere you turn there’s fear mongering, pseudoscience, biased interests and food advertising, just to name a few influences. I have been studying nutrition for over 15 years and I have come to believe that the cure for this madness is to teach individuals to be good scientists and to evaluate these influences in their environment.

Nutrition is a science, first and foremost. That is why my degree in nutrition involved the study of organic chemistry, biochemistry and food science.  Gone are the days when we can we make blanket statements about diets and nutrition, but instead we work with individuals to provide personalized nutrition prescriptions. If you’re looking for the perfect diet for you, keep this in mind: there is no one size fits all when it comes to diet.  When you are reading anything related to nutrition, ask the following questions:  Is this person qualified? Are they balanced? Are they grounded in science?  Are they biased? Do they profit from this?  Here’s a definition I want you to learn: Pseudoscience- a collection of beliefs or practices mistakenly regarded as being based on scientific method. In other words, the information is presented as scientific, but is riddled with half-truths and that’s what makes it so believable.

If you’ve been paying attention over the years,  you’ll remember all of the food fads that have come and gone. Just to name a few: Low-fat, Low-carb, Atkins, Gluten-free (aside from Celiac’s or gluten intolerance), Ketogenic, Alkaline diet.  Currently, carbs are the villain and Protein is king. Sit back and watch as versions of these diets get repackaged and recycled. It can be quite entertaining when you understand the cycles.

So, let’s review some basic nutrition information to help you on your health journey:


  • Technically, this is the amount of heat required to raise the temperature of one kilogram of water 1°C
  • In human nutrition, calories are needed by the body to do work
  • Individual needs vary depending on age, sex, size, genetics and activity levels
  • They are neither bad, nore good, but simply a way of measuring the amount of energy a food provides us

Calorie expenditure is divided between resting metabolic rate, thermic effect of foods (energy used for the digestion of food), non-exercise activity and exercise. Our muscles and organs are the biggest consumers of calories at rest.


  • Nutrients that provide calories or energy
  • Nutrients are substances needed for growth, metabolism, and for other body functions
  • Needed in large amounts

Carbohydrates*—Not the Bad Guys! Should comprise ~45-65% of daily caloric intake . Provide 4 calories/gm. Consume mostly slow-burning carbs such as vegetables, legumes, lentils, dairy, whole grains and fruit

Protein—More Not Always Better! Should comprise ~20-30% of daily caloric intake. Provide 4 calories/gm. Consume mostly lean, unprocessed proteins such as lean meats, eggs, lowfat dairy, tofu, tempeh, edamame

Fat—Is Low the Way to Go?  Should comprise ~15-30%. Provide 9 calories/gm. Consume mostly heart healthy fats such as extra virgin olive oil, fish, avocados, nuts and seeds

*If you’re an endurance athlete, your carb needs tend to be higher.  If you are insulin resistant, overweight or diabetic, you may benefit from a lower carb range of about 40-50% of caloric intake. Your body’s preferred energy source is quality carbohydrates. Follow up with a registered dietitian nutritionist to find which macronutrient balance is right for you.

Soluble Fiber

  • Water soluble
  • Slows the emptying of food from the stomach which may help decrease hunger
  • May help lower blood cholesterol
  • Oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium

Insoluble fiber

  • Speeds transit time of food through the gut
  • Essential for proper bowel function
  • Whole-wheat flour, wheat bran, nuts, beans and vegetables

Both soluble and insoluble fiber contributes to a healthy gut microbiome, which leads to better health.

Phytochemicals-naturally occurring plant chemicals that provide plants with color, odor and flavor. They contribute to our health by the following:

  • Stimulate the immune system
  • Block substances we eat, drink and breathe from becoming carcinogens
  • Reduce the kind of inflammation that makes cancer growth more likely
  • Prevent DNA damage and help with DNA repair
  • Reduce the kind of oxidation damage to cells that can spark cancer
  • Slow the growth rate of cancer cells
  • Help to regulate hormones

This is one reason why it’s important to eat plenty of colorful fruits and vegetables.

A final word on calories. When trying to follow a lower calorie meal plan, quality matters. Choose low energy dense foods (low-calorie) that are nutrient dense, as opposed to foods that are calorically dense but low in nutrition.  Foods that are nutrient dense are lean proteins, vegetables, beans, legumes, lentils, whole grains, fruits and low-fat dairy.  Focus on including more of these foods, while minimizing your intake of highly processed, calorie dense foods.








For the latest recommendations based on science, check out the 2015 Dietary Guidelines for Americans

About the Author
Registered Dietitian Nutritionist and Weight Loss Coach specializing in lifestyle transformation