Conflicting nutrient values charts

Dear Alice,

I have researched health and nutrition online for a while now, and I work out not only with weights and yoga, but martial arts and mountain biking, as well.

Lately while researching online, I've found that a lot of nutritional value charts conflict in numbers. Some charts say that skim milk contains eight grams of protein, some charts say skim milk contains 13 grams of protein. Which charts are right?? This is incredibly frustrating and confusing. I did find out that there is nutrition software available, but it's so expensive and it comes with lots of extra things that only doctors need really, like making charts for patients and what not.

Also, I found information on one site saying that adults should consume 0.8 grams of protein per however many kilos you weigh (I weigh 82 kilos, so that means 66 grams of proteins per day). Another site said that adult females between 25 to 50 kilos just need 55 grams of proteins per day. Also, it's not just protein intake that conflicts with all of these charts online.

If you can help out at all, it would be greatly appreciated. Thank you in advance.

Dear Reader,

There is so much nutrition information available from a host of different sources; it’s not hard to see why you’re confused! It’s not clear where you retrieved your nutrition information from; you may have accessed it from one or more of a number of places, such as published scientific journals, websites, or advertisements. In order to increase the chances of finding accurate nutrition information, it's good to identify, use, and refer back to sources you trust. Another rule of thumb to consider after you’ve determined those reliable resources: when comparing information from multiple sources, make sure that they’re referring to same thing (e.g., same serving size, same type of food, etc.) so that you aren’t comparing values of two different items, or items that are different sizes.  

The U.S. Department of Agriculture (USDA) is generally the one of the most reliable source of nutrition and food-related information for the general public in the United States. The dietary guidelines can be found at the MyPlate website where you can also find sample menus and recipes, a food tracker, body mass index (BMI) calculator, as well as several other useful health and food-related tools. The USDA also has a National Nutrient Database, which is a reliable source for nutrient values for foods. This site is frequently accessed by nutrition researchers and developers of nutrient analysis programs. However, it’s user-friendly enough that even people who aren’t nutrition experts will be able to do a food search during their first visit to the site. That being said, the site can still be a bit confusing. Some products have a number of varieties, such as milk (i.e., a search for "milk" could yield information on both coconut milk and cow's milk), so it's good to be specific about what you're looking for in the database.

The inconsistency you’re noticing may also be due to a range of variability allowed for nutrition labeling. According to the U.S. Food and Drug Administration (FDA) Nutrition Labeling Manual, content labels on calories, sugars, total fat, saturated fat, cholesterol, and sodium are allowed a difference within 20 percent of the product’s true content. What about protein? Similar to other naturally occurring nutrients, protein values listed on the label that meet at least 80 percent of the true content are acceptable. Under the same guidelines outlined in the manual, manufacturers are also allowed to round the content listed on the label to the nearest 1, 5, or 10 increments depending on the nutrient. For example, items with 6.4 grams of protein may end up labeled as six grams of protein. Another trend worth noting is that certain nutrients are more likely to be underreported. This can be problematic over the long-term for people who have chronic diseases such as diabetes, heart disease, and stroke. Also, keep in mind that food inherently varies in nutrient value due to many different factors (e.g., seasonal changes, different batches, soil type etc.) and the testing method behind every label is not standardized. Given that, what you see may not be exactly what you eat!

If you’re interested in analyzing an entire day of food intake — not just one food — comprehensive online programs such as the MyPlate SuperTracker are available. They track your food intake and compare to your daily nutrition needs. The food lists in these programs come from the USDA National Nutrient Database and nutrient needs are based on the Recommended Dietary Allowance (RDA). The RDA for protein you found is what is recommended for people in who are generally in good health, but protein needs can vary depending on a person's health status and physical activity levels. Similarly, RDAs are intended to inform what amounts would meet the daily needs for most people, but individual requirements may vary for specific population groups (e.g., adult men and women). Consider speaking with a registered dietician or your health care provider to find out more about your specific nutrition needs. Another way to have a better sense of your food intake is to prepare and cook your own meals, so that you’re in control of their preparation and amount. You may even enjoy the added creative and satisfying benefits of making your own food!

Lastly, Reader, tracking grams of various nutrients and calories in your daily diet is no simple task and isn’t necessarily sustainable long-term. Hopefully, these new resources will help to clear up your nutrient value confusion, making it easier for you to make healthier eating choices moving forward.

Last updated May 20, 2016
Originally published Dec 17, 2004