The body switches to burning fat based on insulin levels. A very bad diet can make you insulin resistant and eventually have diabetes type 2, but it is reversible.
The difference between a normal person and somebody with insulin resistance is that the latter will feel hungry for longer before starting to burn fat.
Contrary to what the GP says, you need to be low on fat (think extremely skinny) before the body starts scavenging healthy non-fat tissues.
>Contrary to what the GP says, you need to be low on fat (think extremely skinny) before the body starts scavenging healthy non-fat tissues.
The process of converting muscle tissue into glucose falls under the umbrella of gluconeogenesis.
If you burn up your glucose stores, your body may turn to fat (more efficient than converting muscle to glucose), but the body can "skip" the fat burning and turn to the break down of muscle to convert the amino acids (proteins) into glucose. Hint: its build right into your post...Insulin. If a body burns up glucose, and there are high levels of insulin in the blood, then the body will go into gluconeogenesis to breakdown muscle to convert the amino acids into glucose instead of burning fat.
Hyperinsulinemia (https://www.mayoclinic.org/diseases-conditions/type-2-diabet...) is mostly prevalent among those with Type II DM (insulin resistance promoting over-production of insulin in a physiologic attempt to compensate). I don't believe all that many "normal/healthy" individuals have this issue. So while gluconeogenesis is a viable pathway for fuel, in most individuals lipid metabolism will not be skipped over for gluconeogenesis because as mentioned previously it is the slowest and least efficient pathway for ATP production. Someone with a persistent high carb and low fat diet may be in a similar state but with high demand for energy - such as the conditions described in the article - the most efficient pathways will be utilized predominantly, unless the individual went to great lengths to prevent it via their diet.
The difference between a normal person and somebody with insulin resistance is that the latter will feel hungry for longer before starting to burn fat.
Contrary to what the GP says, you need to be low on fat (think extremely skinny) before the body starts scavenging healthy non-fat tissues.