What Kind of Fat is Good Fat?

Below is a case study; we will use this example and make recommendations based on this diet.

Case Study

If Isabel’s diet provides 2200 calories, what is her percentage of calories from fat?  Are these within the recommended range of total fat calories in a healthy diet?  What is considered a healthy percentage of fat calories?

No, Isabel’s overall (and saturated) fat intake is well above the recommended amount. Isabel ingested 993.6 calories from fat, which is 45.163% of her total calories; She also ingested 348.3 calories from saturated fat, which is 15.83% of her total caloric intake. According to DRI (Dietary Reference Intakes), commonly used to set standard dietary guidelines, it is recommended that adults limit themselves to a total fat intake of 20-35% of their calories from fat. Moreover, saturated fats should be limited to under 10%. The American Heart Association suggests that adults struggling with, or at risk for high cholesterol, limit their intake to 6% or less. While an individual’s cholesterol levels are not dependent upon ingested cholesterol, we can help control LDL by eating less saturated fat and trans fat (Grosvenor, 2021). LDL is considered “bad cholesterol” and HDL is considered to be the “good cholesterol”. Saturated fat and trans fat negatively impact cholesterol levels far more than eating cholesterol itself.

  • Suggest two foods you could substitute for her current choices at both breakfast and lunch, that would reduce both her saturated fat and her total fat.  include the fat/saturated fat per serving of the foods you choose.  

One serving of low-fat yogurt (2.45g saturated fat; 3.8g total fat) and a cup of mixed berries (perhaps blueberries and strawberries which have 0.5g total fat and 0g saturated fat) for breakfast; For lunch a turkey sandwich on whole grain bread with tomatoes, lettuce, lean turkey meat (3 slices would contain about 0.41g saturated fat and 1.41g total fat) and a small amount of mustard (Saturated fat, 0.3g and total fat 4.2g for .5 cup) or low-fat mayo (saturated fat in 1 tablespoon is 0.5g and total fat is 3.3g) for added flavor with raw carrot sticks ( 1 cup = 0.1g saturated fat and 0.3g total fat) and broccoli ( 4 spears would contain 0g saturated fat and approximately 0.1g total fat per spear) on the side (Grosvenor, 2021; NUTRITIONIX, 2021).

  • Suggest a dinner meal that would be lower in saturated fat than Isabel’s current dinner and would provide Omega-3 fatty acids.  Why are Omega-3 fatty acids considered good for your overall health?

One of the most well-known ways to get Omega-3 is cold water fish or seafood. I would suggest that Isabel have a salmon filet with mixed vegetables and/or maybe a baked potato. Alpha-linolenic acid (Omega-3) are essential fatty acids because our bodies need them but do not make them. Alpha-linolenic acid can be used to synthesize the longer chains like Omega-6 and Omega-3, so as long as we are not deficient in linoleic acid or alpha linolenic acid, we can simply synthesize the longer-chain nutrients.

Why are these Omega’s important for our health?  Omega fatty acids are important for reproductive system, development of our central nervous system, red blood cells and even skin cells because they are a necessary component of the phospholipid bilayer found in the membranes of our cells. While Omega-6 and Omega-3 are important structural components of cellular membranes, DHA (Omega-3) is intrinsic to the health of our optic retina. If we are deficient in these essential fatty acids, we may end up with unhealthy, scaly, dry, skin, liver problems, developmental problems in growing children, perception issues with vision or hearing, and even issues with wound repair. Luckily this isn’t generally an issue in the United States. We may also consider the ratios of these fatty acids that we are getting. Generally, our diets contain higher than optimal ratio of Omega-6, therefore it is important that we take this into consideration when choosing foods. The American Heart Association suggests at least two servings of fish per week while also consuming non-animal sources like flaxseed, canola oil, or walnuts. I personally do not like fish, but luckily there are supplements and/or other options. If she does not enjoy seafood, Isabel may want to eat a cup ¼ of walnuts to guarantee she is getting adequate amounts of alpha-linolenic acid and ½ cup of almonds to assure she is consuming adequate amounts of linoleic acid. 12g per day is considered adequate for a woman for linoleic acid and 1.1g per day of alpha linoleic acid. The recommended ratio is between 5:1 and 10:1, so the above suggestion falls within those guidelines (Grosvenor, 2021; Marieb & Hoehn, 2019).

4.  Isabel’s weight is stable on this diet.  How can she be short on foods from three food groups and still be getting enough calories? 

In order to answer this question, we can think of physiology; Why do we need nutrients and what are calories? Moreover, what are empty calories? A calorie is a unit, based on the measurement of energy provided by food. While we all need a certain number of calories per day, it is certain that all calories were not created equal. Even alcohol has calories, but we certainly could not live on alcohol. Our bodies use different nutrients for different physiological activities; we use the amino acids in proteins to create tissue, we use glucose to fuel neurons, we use carbohydrates to burn lipids as energy, and that is just the tip of the iceberg. Our bodies are quite good (especially our liver) at synthesizing some of the things we need, such as cholesterol; However, there are some things that we cannot synthesize and those are considered essential nutrients. Some of these processes become a bit complicated when we consider long-term vs. short-term lack of specific nutrients. For instance, in the absence of carbohydrates we can use lipids for ATP synthesis, but this is not a long-term solution. If our bodies cannot use carbohydrates, we may end up with pH imbalance and maybe even ketoacidosis. Unfortunately, many of the issues that arise from eating an unbalanced diet are not so apparent and may take years to affect us. We are born with hunger drive—from an evolutionary vantage point we would not exist if we did not have this drive to seek food. This inherent drive leads us to desire lipids, carbohydrates, and even salt. Today, these things are not difficult to come by and we don’t have to forage or hunt to find them. High-calorie foods are abundant, but that does not mean that they are always high quality. We may satisfy this hunger-drive and fill ourselves with calories that do allow us to survive on a day-to-day basis, but the long-term implications may be severely detrimental. As I mentioned above, a long-term lack or an overabundance of certain nutrients can cause many physiological issues. We must be aware that even an overweight or obese individual can be lacking in certain nutrients. This case study is a great example of how we may be getting enough calories and lipids, but we are still not getting some of the essential nutrients like Omega-3 fatty acids. Obesity puts us at higher risk for diabetes, heart disease, cardiovascular issues, joint problems, non-alcoholic fatty liver disease, and more. If we are lacking certain vitamins, minerals, or essential fatty acids, these issues are compounded, our bodies do not function properly (Grosvenor, 2021; Marieb & Hoehn, 2019).

5.  If Isabel eliminated all fats from her diet, why would that cause her health problems? 

Fat is an important part of the diet. Many of us think of high-fat foods when we talk about fat, but many foods have fat in them—even some fats that our bodies can utilize readily to keep us healthy. Indeed, some fats are essential, and we must consume them. It would be very limiting to eliminate ALL fats and it would be impossible to ingest a balanced diet and consume enough calories without any fat in the diet. Beyond caloric intake needs, lipids form structural components of our cells, provide cushion and warmth for our organs, they provide energy, they give our cells access to fat soluble vitamins and more. While eliminating all fat would be dangerous, it is wise to limit saturated fat, and trans fat while replacing them with healthier options (Grosvenor, 2021).


Grosvenor, M. B. (2021). Visualizing Nutrition: everyday choices. JOHN WILEY.

Marieb, E. N., & Hoehn, K. (2019). Human anatomy & physiology. Hoboken, NJ: Pearson Education.

‘NUTRITIONIX’. (n.d.). Retrieved July 19, 2021, from https://www.nutritionix.com/food/salmon

What’s on your plate? (n.d.). Retrieved July 19, 2021, from https://www.myplate.gov/


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