Nutrition - Current Science
Caution, I am not a nutritionist, although my first job out of college was in a nutrition laboratory. I have tried to stay abreast of the science since.
In this post I am going to discuss three foods we should eat less of, and two we should eat more often.
Most people know that the main food types are carbohydrates, protein, and fat.
For years the guidance was to eat a low fat diet, then later, carbohydrates were to be avoided (e.g. Atkins and Keto diets). The current scientific guidance is more nuanced.
There are three types of food we should consume in small quantities: trans fats, refined carbohydrates (e.g. sugar, white flour), and saturated fats.
Consumption of trans fats are associated with a higher risk of heart disease. Most trans fats are found in processed foods, fried foods, and commercially baked goods like cookies, crackers, and snacks.
To avoid refined carbohydrates, we should avoid soft drinks and fruit juices, and anything with a lot of added sugar. A 12 ounce soft drink contains 10-12 teaspoons of sugar. Fruit juices also have a lot of sugar, though a bit less than soft drinks. Avoid white bread; eat whole grain bread instead. Cakes and cookies not only contain sugar, they contain refined flour.
We need some saturated fat, but most of us eat too much. Saturated fats typically come from animal sources, like red meat and dairy. Most unsaturated fats are drawn from plant sources, like nuts, olives, and avocado.
The majority of Americans don’t eat enough fiber. The recommended amount is 27 grams.
Fiber is found mainly in plant foods such as fruits, vegetables, whole grains and legumes (e.g. beans, peanuts, soy beans, peas). Fiber may be best known for its ability to prevent or relieve constipation. But foods with fiber can help you stay at a healthy weight and lower the risk of diabetes, heart disease and some types of cancer.
Getting enough fiber by eating only fruits and vegetables is difficult. e.g. you have to eat 9 bananas to consume 27 grams of fiber. Whole grains contain a bit more fiber, but it is not likely you can reach the recommended amount of fiber without eating legumes, or taking a supplement (more on this later in a later post). Here are some of the most fiber rich foods (all legumes):
- Split peas, boiled 1 cup (196) 16.0
- Lentils, boiled 1 cup (198) 15.5
- Black beans, boiled 1 cup (172) 15.0
- Cannellini, Navy, Great Northern beans, canned 1 cup (180) 13
- Chia seeds 1 ounce (28.35) 10.0
Protein is the current fad nutrient. There are some wildly extravagant claims about the proper amount. The recommended amount is about 56 grams a day.
If you want to build muscle strength, or you are older than around 60, you need more. The Food and Nutrition Board of the Institute of Medicine and the American College of Sports Medicine recommend 1.2 to 1.7 grams of protein per kilogram of body weight per day.
- 100 pounds (45 kilograms) 54 to 77 grams
- 150 pounds (68 kilograms) 82 to 116 grams
- 200 pounds (91 kilograms) 109 to 155 grams
- 250 pounds (113 kilograms) 136 to 192 grams
Protein is made up of amino acids. There are nine amino acids which we need to eat because our bodies cannot produce them on their own, and which are required to maintain our overall health. (There are other amino acids which we may or may not require depending on individual situations.)
Meat, seafood, dairy foods and eggs contain all nine of the required amino acids (complete protein). There are very few plant sources that contain all nine. Legumes are a good source of lysine but lack methionine, while grains contain sufficient amounts of methionine. Rice and beans, peanut butter and toast, etc are combinations which have all the required amino acids.
A vegan needs to eat legumes and whole grains to obtain complete protein. A vegetarian can eat dairy or eggs and not rely entirely on legumes and whole grains. Sadly, those who eat a lot of “fast food” probably are consuming enough protein, while vegetarians and vegans are often not.
Most of us are also eating a majority of our protein for dinner. Unfortunately, protein consumed at dinner time cannot be stored for later use. A high protein breakfast has been shown to benefit muscle health and to support weight loss by increasing muscle mass, energy expenditure (calories burned), satiety hormones, glucose regulation and by decreasing the desire to snack at night.
The current science suggests strongly that a breakfast with 30 grams of protein and 9 grams of fiber has several health advantages. In a future post I will suggest breakfasts which meet these goals.