Shaun Ward MSc ANutr
The TLC diet, or therapeutic lifestyle changes diet, is a highly regarded diet plan that is backed by some of the world’s leading nutritionists and health organizations. In fact, the diet was even created by the National Institutes of Health (finally, not a self-proclaimed celebrity “nutritionist”).
The main aim of the diet is to improve heart health, and lower levels of total and LDL (“bad”) cholesterol to protect the arteries from cardiovascular disease.
Such a diet is based on the main principles and aims of the national cholesterol education program and the American heart association, to reduce cardiovascular disease and treat hyperlipidemic individuals.
Both these organizations recommend the TLC diet as a first line of therapy for clinical management of high blood cholesterol levels, except for very serious patients who are also required to start drug therapy .
What Is The TLC Diet?
The diet focuses mainly on altering the types of fat that you eat, as well as ensuring an adequate intake of dietary fiber and plant stanols to help lower cholesterol levels.
Much like any healthy diet, it encourages a high consumption of fruits, vegetables, whole grains, legumes, nuts and seeds.
The diet also limits the intake of meat (especially fatty cuts), dairy products, egg yolks, and processed foods.
A nutritional outline of the TLC diet is:
- Eat only enough calories to maintain a healthy weight (if overweight, this requires a caloric deficit)
- Dietary fat should comprise 25-35% of total daily calories
- Under 7% of total daily calories from saturated fat
- No more than 200mg of dietary cholesterol per day
- 10-25 grams of soluble fiber per day
- Consume at least 2 grams of plant sterols or stanols each day
Based on the fundamental concepts of the diet, the main foods to include are:
- Whole grains
- Fish and seafood
Despite this review focusing on the dietary component of the TLC diet, it is worth mentioning that it also advises at least 30 minutes of moderate-intensity physical activity every day.
The Potential Benefits of The TLC Diet
Below is a list of every potential benefit that's backed by credible scientific research:
It May Help Reduce Cholesterol Levels
A vast amount of different types of research has linked high LDL cholesterol levels to cardiovascular diseases such as coronary heart disease – especially when combined with chronic levels of inflammation.
The main nutrients responsible for increasing LDL cholesterol levels are saturated fatty acids, trans fatty acids, and dietary cholesterol – all of which are low on the TLC diet.
From an analytical standpoint, a great thing about the diet is that it has been directly studied, as opposed to having to assess its individual dietary components and make logical assumptions on its overall effectiveness.
Specifically, the TLC diet has reduced levels of LDL cholesterol by ~10% in people with high cholesterol levels . This is very significant when considering that a decrease in cholesterol levels by 10% is estimated to decrease the incidence of cardiovascular disease by ~30%, and mortality rates by ~15% .
These changes in cholesterol levels can occur in just 6 weeks, with greater effects found in men .
Although it is not known, it is thought that the lowering of cholesterol levels is mainly as a result of the increased dietary fiber intake, which has been consistently linked to lowering cholesterol levels and heart disease risk. One of the ways fiber does this is by increasing the excretion of bile acids, which have to be resynthesized with the use of cholesterol, which lowers cholesterol levels in the blood.
The LDL cholesterol lowering effect may also partially be coming from plant stanols and sterols, as these have shown in several meta-analyses to have a dose-response relationship with intakes of 1.5-3 grams per day lowering LDL cholesterol by ~10% . These compounds generally work by reducing the absorption of cholesterol in the gut so more is lost in the feces.
It May Improve Immune Health
A diets effect on immune health is usually a result of its impact on positively influencing gut health.
A study found that just 1 month on the TLC diet can significantly improve immune function by enhancing T cell-mediated immune functions .
The diets ability to lower cholesterol levels may also have some impact on improving immune function. High cholesterol levels are associated with poor immune health by altering the host defense against certain viruses, decreasing the response of antibodies, and suppressing cellular infiltrates in infected tissue .
Hypercholesterolemia has even been associated with a large 40 fold increase in susceptibility to listeria infection , as well as other viruses by impairing antiviral cellular responses and delaying viral clearance from the spleen .
In part, this impairment of the immune system may be due to saturated fatty acids activating various proinflammatory signaling pathways .
It May Reduce Inflammation
The onset of chronic inflammation is typically as a direct result of oxidative stress, which is defined as a disturbance in the balance between the production of reactive oxygen species (free radicals) and antioxidant defenses.
An increasing body of evidence shows that chronic inflammation is the main cause of many modern diseases .
Interestingly, a TLC diet has shown to significantly reduce oxidative stress and may therefore positively impact inflammation.
Importantly, the combination of the diets ability to reduce cholesterol levels, in addition to reducing oxidative stress, should lead to a reduced amount of oxidized LDL cholesterol in the blood – the key contributor to atherosclerosis and plaque build-up on arterial walls .
More research is needed to further analyze the diets effect on inflammation.
The Negatives of The TLC Diet
Below is a list of everything we believe could be viewed as a negative:
It May Be Too Complicated for Some People
Some of the nutritional guidelines of the diet may be hard to follow if someone does not have a good understanding of nutrition.
For example, the diet does not have a specific calorie intake and requires users to self-assess the amount of calories they need to reach or maintain a healthy bodyweight.
Not only is this difficult for the laymen, but it could discourage someone from sticking to the diet in the long-term.
Not only this, but the general public are also going to find it tricky to know if they are within the limits of saturated fat and dietary cholesterol intake, as the average person is unaware of the contents of these nutrients within a range of foods.
It Is Partially Based On Old Science
The recommendation from the TLC diet to reduce saturated fat and cholesterol levels is based on slightly outdated evidence put forth by the American heart association for hypercholesterolemic individuals. This prior recommendation was generally based on older epidemiological and animal studies .
More recent and stronger evidence concludes that saturated fat and dietary cholesterol intake are not the concern they were once thought to be.
For example, a meta-analysis concluded that there is no significant evidence for dietary saturated fat increasing the risk of cardiovascular disease .
Recent scientific reviews also state that saturated fat does not clog the arteries, and that heart disease is a chronic inflammatory condition .
Additionally, although the TLC diet focuses solely on LDL cholesterol, more recent evidence suggests a better indicator for health may be the total cholesterol to HDL cholesterol ratio. This is particularly interesting when considering the studies on the TLC diet that lowered LDL cholesterol levels also reduced HDL cholesterols by ~7% and did not significantly effect the ratio mentioned .
However, for the most part the TLC still is generally based on good nutritional recommendations such as a focus on natural wholefoods that are nutritionally dense.
The TLC diet was even created by the National Institutes of Health and aims to reduce cholesterol levels and protect against cardiovascular disease.
Direct research on the diet so far has shown it is effective for reducing LDL cholesterol levels and inflammation, and improving immune health.
Based on the dietary guidelines and recommendations, the TLC is an extremely good approach to nutrition and health and is one we would recommend for anyone looking to improve their dietary habits.