The human body needs three important things: proteins, carbohydrates and fats/lipids. All of these are called; macronutrients.
Macronutrients are basically nutrients that provide us with energy. We need nutrients because they are needed for growth, metabolism, and for other body functions. The word "macro" means that we need large quantities of these nutrients to allow us to function properly (need a lot to give us energy).
When you look at your diet and what is needed for your body, generally it is recommended that when you eat carbs, proteins, and fats that you eat them both in moderation and choose things that are better for you.
Instead of buying chicken nuggets at McDonalds, buy and cook up some lean chicken breast. Instead of getting that huge steak (that could feed two people) at that restaurant with mashed potatoes, make a smaller steak at home and make a baked potatoes with some steamed broccoli
Everybody is different, so even if you have more meat on your bones (or less) that doesn’t mean that you are unhealthy. The unhealthy part comes how the food affects your body. Sugars, cholesterol, and triglyceride levels are the three biggest issues (epically with fast foods or junk foods since they are the main contributors).
More information below on cholesterol, sugars and triglycerides since they all contribue to weight gain and their potentional adverse health effects.
To go into this further let’s look further into cholesterol, triglycerides and sugars.
We naturally make some cholesterol in our body and we get some from our diet. Basically there are two different types of cholesterol; good and bad.
The good cholesterol usually termed HDL (high density lipoprotein) is small and circulates in our blood stream. It is good because it helps get rid of the bad cholesterol in our body and makes everything run smoothly (this is a very simple breakdown of this subject matter and if you want more info, look it up). High HDL levels help with lowering the chance of heart disease.
The bad cholesterol termed LDL (low density lipoprotein) is much larger. It sticks to the walls of our circulation and hardens to form plaque. This plaque can build up over time and can cause heart attacks (plaque buildup in the heart) or stroke (plaque buildup in the brain). Bad cholesterol can be increased by eating a diet high in saturated fats or trans fats (usually in high amounts with fast food or any processed foods)
With sugars the reason that we say to be careful about how much you ingest is because of the risk of developing diabetes type 2. Sugar which can come from unprocessed sugar products, breads, pasta, some fruits, processed foods become transformed into glucose. Glucose is an energy source for the body. When you have too much glucose your body releases insulin to bring the glucose levels down. Basically glucose is energy while insulin calms you down. When we have too much sugar (glucose) in our body, over time these high levels will cause to body to become “sensitized”. When this happens your insulin won’t work properly and you will have too much glucose running around in your system. Since glucose is an energy source for our body, this uncontrolled energy can overwork various areas of the body (the nerves in your eyes, the nerves in the ends of your feet and hands, your heart, and your kidney’s). Eventually your body will crash and you can go into shock. This severe instability with your body to process sugar is called type 2 diabetes.
Triglycerides are a form of fat produced by the body; basically triglycerides are the stored fat within your body. High levels of triglycerides directly relates to overweight and obesity. Inactivity, eating a diet high in carbohydrates (breads and sugars), smoking and excessive alcohol intake can cause high levels of these triglycerides. High triglycerides relates to high LDL levels, low HDL levels, and higher sugar levels which all can cause heart issues as well as type 2 diabetes (look up the difference between type 1 and type 2 diabetes if you want to know the difference since there is an extreme difference.)
Note: know that some cholesterol, sugars and triglycerides are not bad to have in your body, so don't just cut them out completely! Just consume them in small moderations.
In summary, the best thing to do for your body is this:
1) Eat a well-balanced diet (more veggies, fruits, proteins, complex carbs, and eat health fats; look these up for yourself)
2) Portion control (eat until you are satisfied; not until you are about to keel over; most people have the most trouble with this in general)
3) Talk to your doctor and see if he recommends anything to you specifically (every person is unique in what they should eat)
4) Also talk to your doctor about any history of heart disease, stroke or diabetes within your family since this can increase your chances of developing these complications (genetics are a bitch sometimes).
5) If you have a little fat on you don’t freak, a little fat on the body is healthy and natural; again everyone is different
6) Lastly, it’s okay if you eat some processed foods and some junk foods, just don’t overdo it.